WO2016063632A1 - Silicon carbide substrate and method for producing same - Google Patents

Silicon carbide substrate and method for producing same Download PDF

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Publication number
WO2016063632A1
WO2016063632A1 PCT/JP2015/074741 JP2015074741W WO2016063632A1 WO 2016063632 A1 WO2016063632 A1 WO 2016063632A1 JP 2015074741 W JP2015074741 W JP 2015074741W WO 2016063632 A1 WO2016063632 A1 WO 2016063632A1
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Prior art keywords
silicon carbide
carbide substrate
washing
cleaning
hydrogen peroxide
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PCT/JP2015/074741
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French (fr)
Japanese (ja)
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恭子 沖田
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住友電気工業株式会社
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Application filed by 住友電気工業株式会社 filed Critical 住友電気工業株式会社
Priority to DE112015004795.6T priority Critical patent/DE112015004795T5/en
Priority to JP2015562220A priority patent/JP5924462B1/en
Priority to US15/520,435 priority patent/US10113249B2/en
Priority to CN201580055161.3A priority patent/CN106796877B/en
Publication of WO2016063632A1 publication Critical patent/WO2016063632A1/en
Priority to US16/106,101 priority patent/US10704163B2/en

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
    • C30B33/08—Etching
    • C30B33/10—Etching in solutions or melts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
    • B24B37/042—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/36—Carbides
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002—Preparing wafers
    • H01L21/02005—Preparing bulk and homogeneous wafers
    • H01L21/02008—Multistep processes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02041—Cleaning
    • H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
    • H01L21/02052—Wet cleaning only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02041—Cleaning
    • H01L21/02057—Cleaning during device manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/0445—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising crystalline silicon carbide
    • H01L21/0475—Changing the shape of the semiconductor body, e.g. forming recesses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/30625—With simultaneous mechanical treatment, e.g. mechanico-chemical polishing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
    • H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
    • H01L21/67057—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing with the semiconductor substrates being dipped in baths or vessels
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic System
    • H01L29/1608—Silicon carbide

Definitions

  • the present disclosure relates to a silicon carbide substrate and a method for manufacturing the same.
  • SiC silicon carbide
  • Patent Document 1 Japanese Patent Laid-Open No. 2010-4073 discloses a technique for cleaning a silicon carbide substrate using an aqueous solution containing sulfuric acid and hydrogen peroxide.
  • a silicon carbide substrate according to the present disclosure is a silicon carbide substrate having a main surface, and has a surface roughness (Ra) of 0.1 nm or less, and vanadium, tungsten, molybdenum, platinum, nickel on the main surface.
  • Ra surface roughness
  • Each of titanium, zirconium and chromium has a concentration of 1.0 ⁇ 10 12 atoms / cm 2 or less.
  • a method for manufacturing a silicon carbide substrate according to the present disclosure includes a step of preparing a silicon carbide substrate having a main surface, a step of polishing the main surface of the silicon carbide substrate using an abrasive containing a metal catalyst, and a step of polishing. And a step of cleaning the silicon carbide substrate.
  • the step of cleaning includes a step of cleaning the silicon carbide substrate with aqua regia.
  • FIG. 1 is a partial cross sectional view showing a configuration of a silicon carbide substrate according to a first embodiment.
  • FIG. 5 is a flowchart for schematically illustrating a method for manufacturing a silicon carbide substrate according to the first embodiment.
  • FIG. 3 is a schematic diagram for illustrating one step in the method for manufacturing a silicon carbide substrate according to the first embodiment. It is a schematic block diagram of the grinding
  • FIG. 3 is a schematic diagram for illustrating one step in the method for manufacturing a silicon carbide substrate according to the first embodiment. It is a schematic block diagram of the washing
  • FIG. 5 is a flowchart for schematically illustrating a cleaning method in the method for manufacturing a silicon carbide substrate according to the first embodiment. It is a flowchart for demonstrating schematically the washing
  • FIG. 10 is a flowchart for schematically explaining a cleaning method in a cleaning method according to Modification 2.
  • a chemical mechanical polishing method called a CMP (Chemical Mechanical Polishing) method is employed.
  • CMP Chemical Mechanical Polishing
  • an abrasive containing a metal catalyst that modifies the surface by catalytic action is used so as to increase the oxidizing power of the oxidizing agent.
  • the metal catalyst an oxide layer having a lower hardness than silicon carbide is formed on the surface of the silicon carbide substrate. Since polishing is promoted by removing the oxide layer with a mechanical force, a high polishing rate and a good surface roughness can be obtained.
  • a silicon carbide epitaxial layer (hereinafter also referred to as an epi layer) is grown on a silicon carbide substrate after polishing using a polishing agent containing a metal catalyst, the silicon carbide epi layer grows locally and abnormally. The surface roughness of the surface of the layer may increase.
  • a silicon carbide substrate according to the present disclosure is a silicon carbide substrate having a main surface, the surface roughness (Ra) is 0.1 nm or less, and vanadium, tungsten, molybdenum, platinum on the main surface
  • Ra surface roughness
  • nickel, titanium, zirconium and chromium has a concentration of 1.0 ⁇ 10 12 atoms / cm 2 or less.
  • the main surface means a surface on which devices such as transistors and diodes are formed.
  • the surface roughness (Ra) of the main surface of the silicon carbide substrate can be easily reduced to 0.1 nm or less by using an abrasive containing a metal catalyst.
  • the metal catalyst contains, for example, at least one metal element selected from the group consisting of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium. These metal elements have a catalytic action that cuts the bonds of the atomic arrangement on the surface of silicon carbide and facilitates the oxidation of the surface. Therefore, an oxide layer having a lower hardness than silicon carbide can be suitably formed on the main surface of the silicon carbide substrate. Therefore, polishing of the silicon carbide substrate can be promoted.
  • the metal derived from the metal catalyst attached to the main surface of the silicon carbide substrate remains on the main surface.
  • material molecules of the epi layer may selectively adhere to the portion where the metal remains in the initial stage of epitaxial growth.
  • the epi layer grows abnormally. If the epi layer partially grows abnormally, the surface roughness of the surface of the epi layer increases. Therefore, in order to reduce the surface roughness of the epilayer surface, it is required to reduce the metal remaining on the main surface of the silicon carbide substrate.
  • the surface roughness of the epilayer surface grown on the main surface of the silicon carbide substrate can be reduced.
  • each concentration of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium on the main surface of the silicon carbide substrate is 2.0 ⁇ 10 11 atoms / cm 2 or less.
  • each of the concentrations of potassium, sodium, calcium, iron, copper, aluminum and tin on the main surface of the silicon carbide substrate is It is 1.0 ⁇ 10 10 atoms / cm 2 or less.
  • the diameter of the silicon carbide substrate is 100 mm or more.
  • a method for manufacturing a silicon carbide substrate according to the present disclosure includes a step of preparing a silicon carbide substrate having a main surface, a step of polishing the main surface of the silicon carbide substrate using an abrasive containing a metal catalyst, And a step of cleaning the silicon carbide substrate after the polishing step.
  • the step of cleaning includes a step of cleaning the silicon carbide substrate with aqua regia.
  • the abrasive is at least selected from the group consisting of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium as a metal catalyst. Contains a kind of metal element.
  • the step of cleaning is performed after the step of cleaning the silicon carbide substrate with sulfuric acid / hydrogen peroxide and the step of cleaning with sulfuric acid / hydrogen peroxide.
  • a step of cleaning the silicon carbide substrate with ammonia water is performed after the step of washing with ammonia overwater.
  • the step of cleaning further includes a step of cleaning the silicon carbide substrate with hydrochloric acid overwater after the step of cleaning with aqua regia, and a step of cleaning the silicon carbide substrate with hydrofluoric acid after the step of cleaning with hydrochloric acid overwater.
  • the “metal other than the metal catalyst” includes, for example, at least one metal selected from the group consisting of potassium, sodium, calcium, iron, copper, aluminum, and tin.
  • a step of washing with sulfuric acid / hydrogen peroxide a step of washing with ammonia / hydrogen peroxide, a step of washing with aqua regia, a step of washing with hydrochloric acid / hydrogen peroxide.
  • the treatment time is set to 15 minutes or more.
  • the step of cleaning further includes a step of cleaning the silicon carbide substrate with ammonia hydrogen peroxide.
  • a step of cleaning the silicon carbide substrate with aqua regia is performed. According to this, the organic substance adhering to the main surface of the silicon carbide substrate can be reduced, and the metal catalyst remaining on the main surface of the silicon carbide substrate and metals other than the metal catalyst can be reduced.
  • the treatment time is set to 15 minutes or longer in each of the step of washing with ammonia perwater and the step of washing with aqua regia.
  • the cleaning step further includes a step of cleaning the silicon carbide substrate with sulfuric acid / hydrogen peroxide.
  • a step of washing with aqua regia is performed.
  • the step of cleaning further includes a step of cleaning the silicon carbide substrate with hydrofluoric acid after the step of cleaning with aqua regia.
  • the treatment time is 15 minutes or more in each of the step of washing with sulfuric acid / hydrogen peroxide, the step of washing with aqua regia and the step of washing with hydrofluoric acid. To do.
  • the aqua regia in the mixed liquid in which aqua regia and ultrapure water are mixed is used.
  • the volume concentration of water is 50% or more and 100% or less.
  • the sulfuric acid contained in the sulfuric acid / hydrogen peroxide in the step of washing with sulfuric acid / hydrogen peroxide Is 1 to 5 times the volume of the ultrapure water contained in the sulfuric acid hydrogen peroxide, and the volume of the hydrogen peroxide solution contained in the sulfuric acid hydrogen peroxide is 1 to 3 times the volume of the ultrapure water contained in the sulfuric acid hydrogen peroxide. Is less than double.
  • the volume of the ammonia aqueous solution contained in the ammonia perwater is The volume of the ultrapure water contained is 1/10 times or more and 1 time or less, and the volume of the hydrogen peroxide solution contained in the ammonia perwater is 1/10 times or more and 1 time or less of the volume of the ultrapure water contained in the ammonia overwater. is there.
  • the temperature of the silicon carbide substrate is set to 40 ° C. or lower in the cleaning step.
  • FIG. 1 is a partial cross sectional view showing a configuration of silicon carbide substrate 10 according to the first embodiment.
  • silicon carbide substrate 10 has a main surface 10A.
  • Silicon carbide substrate 10 is made of, for example, a polytype 4H hexagonal silicon carbide single crystal.
  • Silicon carbide substrate 10 includes an n-type impurity such as nitrogen.
  • the impurity concentration in silicon carbide substrate 10 is, for example, 5.0 ⁇ 10 18 cm ⁇ 3 or more and 2.0 ⁇ 10 19 cm ⁇ 3 or less.
  • Silicon carbide substrate 10 has a diameter of, for example, 100 mm or more (4 inches or more), or 150 mm or more (6 inches).
  • the surface roughness (Ra) of the main surface 10A is 0.1 nm or less. “Surface roughness (Ra)” is a value measured according to JIS B0601. The surface roughness (Ra) can be measured using, for example, an atomic force microscope (AFM).
  • AFM atomic force microscope
  • the AFM for example, “Dimension 300” manufactured by Veeco can be used.
  • the AFM cantilever (probe) for example, model “NCHV-10V” manufactured by Bruker can be used.
  • the measurement mode is the tapping mode
  • the measurement region in the tapping mode is 10 ⁇ m square
  • the pitch is 40 nm
  • the measurement depth is 1.0 ⁇ m.
  • the scanning speed in the measurement area is set to 5 seconds per cycle
  • the number of data per scanning line is set to 512 points
  • the number of scanning lines is set to 512.
  • the displacement control of the cantilever is set to 15.50 nm.
  • Main surface 10A may be a ⁇ 0001 ⁇ plane, for example, or a plane having a predetermined off angle (for example, an off angle of 10 ° or less) with respect to the ⁇ 0001 ⁇ plane.
  • Each concentration of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium on main surface 10A is 1.0 ⁇ 10 6 atoms / cm 2 or more, and 1.0 ⁇ 10 12 atoms. / Cm 2 or less. More preferably, each concentration of potassium, sodium, calcium, iron, copper, aluminum, and tin on the main surface 10A is 1.0 ⁇ 10 10 atoms / cm 2 or less.
  • the concentration of the metal impurity on the main surface 10A can be measured by ICP-MS (Inductively Coupled Plasma Mass Spectrometry). Specifically, for example, ICP-MS7500 manufactured by Agilent can be used.
  • the method for manufacturing silicon carbide substrate 10 according to the present embodiment includes a preparation step (S10), a polishing step (S20), and a cleaning step (S30).
  • silicon carbide substrate 10 cut out from the single crystal silicon carbide ingot is prepared.
  • silicon carbide substrate 10 according to the present embodiment is made of, for example, a polytype 4H hexagonal silicon carbide single crystal and has a main surface 11A.
  • the polishing apparatus 100 used in the first embodiment includes a substrate holding unit 101, a rotating surface plate unit 104, a polishing cloth 102, and an abrasive supply unit 108.
  • the substrate holding unit 101 includes a pressure head that rotates about a rotation axis C2 by a shaft (not shown).
  • the rotating surface plate portion 104 includes a disk-like portion that rotates about the rotation axis C ⁇ b> 1 by the shaft 106.
  • the polishing cloth 102 is fixed to the upper surface of the rotating surface plate portion 104.
  • An abrasive supply unit 108 for supplying the abrasive 110 is provided above the rotating platen unit 104.
  • the silicon carbide substrate 10 is attached to the lower surface of the pressure head of the substrate holding unit 101, and the main surface 11A is disposed so as to face the polishing cloth 102. Then, the pressure head is lowered and a predetermined pressure is applied to the silicon carbide substrate 10. Next, the substrate holding unit 101 and the rotating surface plate unit 104 are rotated in the same direction (the direction of the arrow in FIG. 4) while supplying the polishing agent 110 from the polishing agent supply unit 108 to the polishing pad 102.
  • the substrate holding unit 101 and the rotating surface plate unit 104 may be rotated in the opposite directions, or one may be fixed and the other may be rotated.
  • the polishing agent 110 used in the polishing step (S20) includes abrasive grains, an oxidizing agent, and a metal catalyst.
  • the abrasive is a material softer than silicon carbide in order to reduce the surface roughness and the work-affected layer.
  • As the abrasive grains for example, colloidal silica, fume silica, alumina, diamond, or the like is used.
  • the oxidizing agent forms an oxide film on the main surface 11A.
  • the oxidizing agent for example, hydrogen peroxide, sodium hypochlorite, barium percarbonate or the like is used.
  • the metal catalyst contains at least one metal element selected from the group consisting of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium.
  • metal catalyst for example, sodium tungstate, sodium vanadate, sodium molybdate and the like are used.
  • the abrasive 110 is preferably pH 6 or lower or pH 9.5 or higher, more preferably pH 4 or lower and pH 10.5 or higher.
  • the pH of the abrasive 110 is controlled by inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid, organic acids such as formic acid, acetic acid, oxalic acid, citric acid, malic acid, tartaric acid, succinic acid, phthalic acid and fumaric acid, It can be controlled by adding an inorganic alkali such as KOH, NaOH or NH 4 OH, an organic alkali such as choline, amine, TMAH (tetramethylammonium hydroxide), or a salt thereof.
  • inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid
  • organic acids such as formic acid, acetic acid, oxalic acid, citric acid, malic acid, tartaric acid, succinic acid
  • the surface roughness (Ra) of the main surface 10A after the polishing step (S20) is 0.1 nm or less.
  • the main surface 10A may have foreign matters such as dust or the abrasive used in the polishing step (S20) attached thereto. Specifically, abrasive grains, organic substances, metals, and the like may adhere to the main surface 10A.
  • the metal adhering to 10 A of main surfaces originates in the metal catalyst contained in an abrasive
  • the cleaning device 120 used in the first embodiment includes a cleaning processing layer 122, a pump 124, a filter 126, and a heater 128.
  • the cleaning process is performed by immersing silicon carbide substrate 10 in cleaning process layer 122 filled with cleaning liquid 130 for a certain period of time. At least a part of foreign matter such as dust, organic matter and metal adhering to the immersed main surface 10A is dissolved in the cleaning liquid 130 and removed.
  • the cleaning liquid 130 is constantly circulated by the pump 124 and filtered by the filter 126.
  • the cleaning liquid 130 is maintained at a desired temperature by performing temperature control using the heater 128.
  • the cleaning step (S30) includes, for example, sulfuric acid / aqueous cleaning (S31), ammonia / aqueous cleaning (S32), aqua regia cleaning (S33), hydrochloric acid / overwater cleaning (S34), and hydrofluoric acid cleaning.
  • a plurality of steps are performed in the order of (S35).
  • an ultrapure water cleaning process may be performed. This is to wash away the cleaning liquid remaining on the main surface 10A.
  • ultrapure water for example, water having an electrical resistivity of 15 M ⁇ ⁇ cm or more, an organic substance (TOC: Total Organ Carbon) of less than 100 ppb, and a residual silica of less than 10 ppb can be used. The same applies to ultrapure water used in the subsequent steps.
  • TMAH and a surfactant remove abrasive grains such as colloidal silica attached to the main surface 10A in the polishing step (S20).
  • sulfuric acid / hydrogen peroxide washing step (S31) organic substances adhering to the main surface 10A are removed by sulfuric acid / hydrogen peroxide.
  • Sulfuric acid / hydrogen peroxide is a solution in which sulfuric acid, hydrogen peroxide water, and ultrapure water are mixed.
  • sulfuric acid for example, concentrated sulfuric acid having a mass percentage concentration of 98% can be used.
  • hydrogen peroxide solution for example, a hydrogen peroxide solution having a mass percentage concentration of 30% can be used. The same applies to the hydrogen peroxide solution used in the subsequent steps.
  • the volume ratio of sulfuric acid, hydrogen peroxide water, and ultrapure water contained in the sulfuric acid perwater is, for example, 1 (sulfuric acid): 1 (hydrogen peroxide water): 1 (ultra pure water).
  • the volume ratio of sulfuric acid, hydrogen peroxide solution, and ultrapure water is 1 (sulfuric acid): 1 (hydrogen peroxide solution): 1 (ultrapure water) to 5 (sulfuric acid): 3 (peroxidation) Hydrogen water): 1 (ultra pure water).
  • the volume of sulfuric acid is 1 to 5 times the volume of ultrapure water.
  • the volume of hydrogen peroxide water is 1 to 3 times the volume of ultrapure water.
  • Ammonia overwater is a solution in which an aqueous ammonia solution, hydrogen peroxide solution, and ultrapure water are mixed.
  • an aqueous ammonia solution for example, an aqueous ammonia solution having a mass percentage concentration of 28% can be used.
  • the volume ratio of the aqueous ammonia solution, the hydrogen peroxide solution, and the ultrapure water contained in the ammonia overwater is, for example, 1 (aqueous ammonia solution): 1 (hydrogen peroxide solution): 10 (ultrapure water):
  • the volume ratio of the aqueous ammonia solution, the hydrogen peroxide solution, and the ultrapure water is 1 (ammonia aqueous solution): 1 (hydrogen peroxide solution): 10 (ultrapure water) to 1 (ammonia aqueous solution): 1 (Hydrogen peroxide solution): 1 (ultra pure water).
  • the volume of the aqueous ammonia solution is 1/10 to 1 times the volume of ultrapure water.
  • the volume of hydrogen peroxide water is 1/10 times or more and 1 time or less of the volume of ultrapure water.
  • Aqua regia is a solution in which hydrochloric acid and nitric acid are mixed.
  • aqua regia a solution in which hydrochloric acid and nitric acid are mixed.
  • the volume ratio of aqua regia or aqua regia contained in hydrochloric acid, nitric acid, and ultrapure water is, for example, 3 (hydrochloric acid): 1 (nitric acid): 0 (ultra pure water).
  • the volume ratio of hydrochloric acid, nitric acid, and ultrapure water is 3 (hydrochloric acid): 1 (nitric acid): 0 (ultrapure water) to 3 (hydrochloric acid): 1 (nitric acid): 2 (ultrapure water).
  • the volume concentration of the aqua regia in a mixed solution in which aqua regia (mixed solution of hydrochloric acid and nitric acid) and ultrapure water are mixed is 50% or more and 100% or less.
  • hydrochloric acid overwater washing step (S34) at least a part of the metal other than the metal catalyst remaining on the main surface 10A is removed by hydrochloric acid overwater.
  • hydrochloric acid for example, concentrated hydrochloric acid having a mass percentage concentration of 98% can be used.
  • the volume ratio of hydrochloric acid, hydrogen peroxide solution, and ultrapure water contained in the hydrochloric acid overwater is, for example, 1 (hydrochloric acid): 1 (hydrogen peroxide solution): 10 (ultrapure water).
  • the volume ratio of hydrochloric acid, hydrogen peroxide solution, and ultrapure water is 1 (hydrochloric acid): 1 (hydrogen peroxide solution): 10 (ultrapure water) to 1 (hydrochloric acid): 1 (peroxidation).
  • the volume of hydrochloric acid is 1/10 to 1/5 times the volume of ultrapure water.
  • the volume of the hydrogen peroxide solution is 1/10 to 1/5 times the volume of ultrapure water.
  • the silicon oxide film is removed by hydrofluoric acid.
  • concentration of hydrofluoric acid in the mixed liquid in which hydrofluoric acid and ultrapure water are mixed is, for example, 30%.
  • concentration of hydrofluoric acid in the mixed solution is 20% or more and 50% or less.
  • the processing time of each of the above steps (S31) to (S35) is, for example, 30 minutes.
  • the treatment time is preferably 15 minutes or longer, more preferably 30 minutes or longer.
  • the temperature of silicon carbide substrate 10 is, for example, room temperature. In each step, the temperature of silicon carbide substrate 10 is preferably 40 ° C. or lower.
  • silicon carbide substrate 10 (FIG. 1) having main surface 10A in which the metal concentration is reduced is obtained by the cleaning step (S30).
  • the cleaning step (S30) in the method for manufacturing silicon carbide substrate 10 according to the present embodiment is not limited to the above. Below, the modification of a washing
  • the cleaning step is, for example, ammonia overwater cleaning (S32). It includes a plurality of steps performed in the order of aqua regia cleaning (S33). After each cleaning step, an ultrapure water cleaning step may be performed. In addition, an alkali washing
  • the cleaning process is performed in the order of, for example, sulfuric acid / hydrogen peroxide cleaning (S31), ammonia / hydrogen peroxide cleaning (S32), aqua regia cleaning (S33), and hydrofluoric acid cleaning (S35).
  • S31 sulfuric acid / hydrogen peroxide cleaning
  • S32 ammonia / hydrogen peroxide cleaning
  • S33 aqua regia cleaning
  • S35 hydrofluoric acid cleaning
  • an ultrapure water cleaning process may be performed.
  • an alkali washing process may be implemented before a sulfuric acid perwater washing process.
  • Table 1 shows the relationship between the metal concentration present on main surface 10A and the method for cleaning silicon carbide substrate 10.
  • the silicon carbide substrate 10 according to each of samples 1 to 3 was manufactured by the manufacturing method according to the first embodiment.
  • the cleaning step (S30) relating to each of samples 1 to 3 will be described below.
  • the sulfuric acid / hydrogen peroxide washing step (S31) was performed.
  • the volume ratio of sulfuric acid, hydrogen peroxide solution, and ultrapure water contained in the sulfuric acid / hydrogen peroxide is 1 (sulfuric acid): 1 (hydrogen peroxide solution): 1 (ultrapure water).
  • the treatment time in the sulfuric acid / hydrogen peroxide washing step (S31) was 30 minutes, and the liquid temperature of sulfuric acid / hydrogen peroxide was room temperature.
  • an ammonia overwater washing step (S32) was performed.
  • the volume ratio of the aqueous ammonia solution, the hydrogen peroxide solution, and the ultrapure water contained in the ammonia overwater is 1 (aqueous ammonia solution): 1 (hydrogen peroxide solution): 10 (ultrapure water):
  • the treatment time in the ammonia overwater washing step (S32) was 30 minutes, and the liquid temperature of the ammonia overwater was room temperature.
  • the volume ratio of hydrochloric acid, nitric acid and ultrapure water contained in aqua regia is 3 (hydrochloric acid): 1 (nitric acid): 0 (ultrapure water).
  • the treatment time in the aqua regia washing step (S33) was 30 minutes, and the aqua regia liquid temperature was room temperature.
  • a hydrochloric acid overwater washing step (S34) was performed.
  • the volume ratio of hydrochloric acid, hydrogen peroxide solution, and ultrapure water contained in the hydrochloric acid overwater is 1 (hydrochloric acid): 1 (hydrogen peroxide solution): 10 (ultrapure water).
  • the treatment time in the hydrochloric acid overwater washing step (S34) was 30 minutes, and the aqua regia liquid temperature was room temperature.
  • a hydrofluoric acid cleaning step (S35) was performed.
  • the concentration of hydrofluoric acid in the mixed liquid in which hydrofluoric acid and ultrapure water are mixed is 30%.
  • the treatment time in the hydrofluoric acid cleaning step (S35) was 30 minutes, and the liquid temperature of hydrofluoric acid was room temperature. That is, in the cleaning step (S30) according to each of samples 1 to 3, the temperature of silicon carbide substrate 10 during cleaning was 40 ° C. or lower. All the cleaning steps are performed at room temperature. The reason is as follows. Since silicon carbide is chemically inert, it takes a long time to oxidize and lift off the surface.
  • the metal concentration is vanadium (V), tungsten (W), molybdenum (Mo), platinum (Pt), nickel (Ni), titanium (Ti). Both chromium and chromium (Cr) show values of 1 ⁇ 10 12 atoms / cm 2 or less.
  • concentrations of vanadium (V) present on the main surface 10A of sample 2 and the main surface 10A of sample 3 were 72 ⁇ 10 9 atoms / cm 2 and 16 ⁇ 10 9 atoms / cm 2 , respectively.
  • Table 3 shows measurement results of metal concentrations other than the metal catalyst present on the main surface 10A.
  • “ND” is lower than the detection lower limit (1 ⁇ 10 7 atoms / cm 2 ), and thus indicates that it was not detected.

Abstract

This method for producing a silicon carbide substrate comprises: a step (S10) for preparing a silicon carbide substrate having a main surface; a step (S20) for polishing the main surface of the silicon carbide substrate using a polishing agent that contains a metal catalyst; and a step (S30) for cleaning the silicon carbide substrate after the polishing step. The cleaning step contains a step (S33) for cleaning the silicon carbide substrate with aqua regia.

Description

炭化珪素基板およびその製造方法Silicon carbide substrate and method for manufacturing the same
　本開示は、炭化珪素基板およびその製造方法に関する。 The present disclosure relates to a silicon carbide substrate and a method for manufacturing the same.
　近年、半導体装置の高耐圧化、低損失化などを可能とするため、半導体装置を構成する材料として炭化珪素（ＳｉＣ）の採用が進められている。 In recent years, in order to enable a semiconductor device to have a high breakdown voltage and low loss, silicon carbide (SiC) has been adopted as a material constituting the semiconductor device.
　炭化珪素基板の製造工程においては、炭化珪素インゴットからスライスされた炭化珪素基板を研磨することで表面を平滑化した後、炭化珪素基板を洗浄する。たとえば、特許文献１（特開２０１０－４０７３号公報）には、硫酸と過酸化水素水とを含む水溶液を用いて炭化珪素基板を洗浄する技術が開示されている。 In the silicon carbide substrate manufacturing process, a silicon carbide substrate sliced from a silicon carbide ingot is polished to smooth the surface, and then the silicon carbide substrate is cleaned. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2010-4073) discloses a technique for cleaning a silicon carbide substrate using an aqueous solution containing sulfuric acid and hydrogen peroxide.
特開２０１０－４０７３号公報JP 2010-4073 A
　本開示に係る炭化珪素基板は、主面を有する炭化珪素基板であって、表面粗さ（Ｒａ）が０．１ｎｍ以下であり、かつ、上記主面において、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムのそれぞれの濃度は、いずれも１．０×１０１２ａｔｏｍｓ／ｃｍ２以下である。 A silicon carbide substrate according to the present disclosure is a silicon carbide substrate having a main surface, and has a surface roughness (Ra) of 0.1 nm or less, and vanadium, tungsten, molybdenum, platinum, nickel on the main surface. Each of titanium, zirconium and chromium has a concentration of 1.0 × 10 12 atoms / cm 2 or less.
　本開示に係る炭化珪素基板の製造方法は、主面を有する炭化珪素基板を準備する工程と、炭化珪素基板の主面を、金属触媒を含む研磨剤を用いて研磨する工程と、研磨する工程後に、炭化珪素基板を洗浄する工程とを備える。洗浄する工程は、炭化珪素基板を王水で洗浄する工程を含む。 A method for manufacturing a silicon carbide substrate according to the present disclosure includes a step of preparing a silicon carbide substrate having a main surface, a step of polishing the main surface of the silicon carbide substrate using an abrasive containing a metal catalyst, and a step of polishing. And a step of cleaning the silicon carbide substrate. The step of cleaning includes a step of cleaning the silicon carbide substrate with aqua regia.
実施の形態１に係る炭化珪素基板の構成を示す部分断面図である。1 is a partial cross sectional view showing a configuration of a silicon carbide substrate according to a first embodiment. 実施の形態１に係る炭化珪素基板の製造方法を概略的に説明するためのフロー図である。FIG. 5 is a flowchart for schematically illustrating a method for manufacturing a silicon carbide substrate according to the first embodiment. 実施の形態１に係る炭化珪素基板の製造方法における一工程を説明するための概略図である。FIG. 3 is a schematic diagram for illustrating one step in the method for manufacturing a silicon carbide substrate according to the first embodiment. 研磨工程に用いられる研磨装置の概略構成図である。It is a schematic block diagram of the grinding | polishing apparatus used for a grinding | polishing process. 実施の形態１に係る炭化珪素基板の製造方法における一工程を説明するための概略図である。FIG. 3 is a schematic diagram for illustrating one step in the method for manufacturing a silicon carbide substrate according to the first embodiment. 洗浄工程に用いられる洗浄装置の概略構成図である。It is a schematic block diagram of the washing | cleaning apparatus used for a washing | cleaning process. 実施の形態１に係る炭化珪素基板の製造方法における洗浄方法を概略的に説明するためのフロー図である。FIG. 5 is a flowchart for schematically illustrating a cleaning method in the method for manufacturing a silicon carbide substrate according to the first embodiment. 変形例１に係る洗浄方法を概略的に説明するためのフロー図である。It is a flowchart for demonstrating schematically the washing | cleaning method which concerns on the modification 1. FIG. 変形例２に係る洗浄方法における洗浄方法を概略的に説明するためのフロー図である。10 is a flowchart for schematically explaining a cleaning method in a cleaning method according to Modification 2. FIG.
　[実施形態の説明]
　炭化珪素基板の研磨には、例えば、ＣＭＰ（Chemical　Mechanical　Polishing）法と呼ばれる化学機械的研磨法が採用される。ＣＭＰ法においては、高い研磨速度で良好な表面粗度を実現するために、例えば、酸化剤の酸化力を高めるよう、表面を触媒作用により改質させる金属触媒を含んだ研磨剤が使用される。金属触媒によって、炭化珪素基板の表面には、炭化珪素よりも硬度が低い酸化層が形成される。酸化層を機械的な力で除去することによって研磨が促進されるため、高い研磨速度と良好な表面の面粗さとを得ることができる。 [Description of Embodiment]
For polishing the silicon carbide substrate, for example, a chemical mechanical polishing method called a CMP (Chemical Mechanical Polishing) method is employed. In the CMP method, in order to achieve good surface roughness at a high polishing rate, for example, an abrasive containing a metal catalyst that modifies the surface by catalytic action is used so as to increase the oxidizing power of the oxidizing agent. . By the metal catalyst, an oxide layer having a lower hardness than silicon carbide is formed on the surface of the silicon carbide substrate. Since polishing is promoted by removing the oxide layer with a mechanical force, a high polishing rate and a good surface roughness can be obtained.
　しかしながら、金属触媒を含む研磨剤を用いて研磨した後、炭化珪素基板上に炭化珪素エピタキシャル層（以下、エピ層とも称する）を成長させると、炭化珪素エピ層が局所的に異常成長し、エピ層の表面の面粗さが大きくなってしまうことがある。 However, when a silicon carbide epitaxial layer (hereinafter also referred to as an epi layer) is grown on a silicon carbide substrate after polishing using a polishing agent containing a metal catalyst, the silicon carbide epi layer grows locally and abnormally. The surface roughness of the surface of the layer may increase.
　最初に本開示の実施態様を列記して説明する。
　（１）本開示に係る炭化珪素基板は、主面を有する炭化珪素基板であって、表面粗さ（Ｒａ）が０．１ｎｍ以下であり、かつ、主面において、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムのそれぞれの濃度はいずれも、１．０×１０１２ａｔｏｍｓ／ｃｍ２以下である。ここで主面とは、トランジスタ、ダイオードなどのデバイスが形成される面を意味する。 First, embodiments of the present disclosure will be listed and described.
(1) A silicon carbide substrate according to the present disclosure is a silicon carbide substrate having a main surface, the surface roughness (Ra) is 0.1 nm or less, and vanadium, tungsten, molybdenum, platinum on the main surface Each of nickel, titanium, zirconium and chromium has a concentration of 1.0 × 10 12 atoms / cm 2 or less. Here, the main surface means a surface on which devices such as transistors and diodes are formed.
　ＣＭＰ法において、金属触媒を含んだ研磨剤を用いることにより、炭化珪素基板の主面の表面粗さ（Ｒａ）を０．１ｎｍ以下にすることが容易になる。 In the CMP method, the surface roughness (Ra) of the main surface of the silicon carbide substrate can be easily reduced to 0.1 nm or less by using an abrasive containing a metal catalyst.
　上記金属触媒は、例えば、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムからなる群より選ばれた少なくとも１種の金属元素を含んでいる。これらの金属元素は炭化珪素の表面の原子配列の結合の手を切断し、表面を酸化させやすくする触媒作用を持つ。よって、炭化珪素基板の主面に炭化珪素よりも硬度が低い酸化層を好適に形成できる。そのため、炭化珪素基板の研磨を促進できる。 The metal catalyst contains, for example, at least one metal element selected from the group consisting of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium. These metal elements have a catalytic action that cuts the bonds of the atomic arrangement on the surface of silicon carbide and facilitates the oxidation of the surface. Therefore, an oxide layer having a lower hardness than silicon carbide can be suitably formed on the main surface of the silicon carbide substrate. Therefore, polishing of the silicon carbide substrate can be promoted.
　しかしながら、上記金属触媒を含む研磨剤を用いて炭化珪素基板を研磨した後に、炭化珪素基板を洗浄しても、炭化珪素基板の主面に付着した金属触媒に由来する金属が主面に残存する場合がある。主面に金属が残存した炭化珪素基板上にエピ層を成長させると、エピタキシャル成長の初期段階において、金属が残存している部分にエピ層の材料分子が選択的に付着する場合がある。その結果、エピ層が異常成長する。エピ層が部分的に異常成長すると、エピ層の表面の面粗さが大きくなる。したがって、エピ層の表面の面粗さを小さくするためには、炭化珪素基板の主面に残存する金属を低減することが求められる。 However, even if the silicon carbide substrate is cleaned after polishing the silicon carbide substrate using the abrasive containing the metal catalyst, the metal derived from the metal catalyst attached to the main surface of the silicon carbide substrate remains on the main surface. There is a case. When an epi layer is grown on a silicon carbide substrate having a metal remaining on the main surface, material molecules of the epi layer may selectively adhere to the portion where the metal remains in the initial stage of epitaxial growth. As a result, the epi layer grows abnormally. If the epi layer partially grows abnormally, the surface roughness of the surface of the epi layer increases. Therefore, in order to reduce the surface roughness of the epilayer surface, it is required to reduce the metal remaining on the main surface of the silicon carbide substrate.
　上記炭化珪素基板においては、炭化珪素基板の主面に成長するエピ層表面の面粗さを低減できる。 In the silicon carbide substrate, the surface roughness of the epilayer surface grown on the main surface of the silicon carbide substrate can be reduced.
　（２）上記炭化珪素基板において好ましくは、炭化珪素基板の主面において、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムのそれぞれの濃度はいずれも、２．０×１０１１ａｔｏｍｓ／ｃｍ２以下である。 (2) In the silicon carbide substrate, preferably, each concentration of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium on the main surface of the silicon carbide substrate is 2.0 × 10 11 atoms / cm 2 or less.
　（３）上記（１）または（２）に記載の炭化珪素基板において好ましくは、炭化珪素基板の主面における、カリウム、ナトリウム、カルシウム、鉄、銅、アルミニウムおよび錫のそれぞれの濃度はいずれも、１．０×１０１０ａｔｏｍｓ／ｃｍ２以下である。 (3) Preferably in the silicon carbide substrate according to (1) or (2) above, each of the concentrations of potassium, sodium, calcium, iron, copper, aluminum and tin on the main surface of the silicon carbide substrate is It is 1.0 × 10 10 atoms / cm 2 or less.
　（４）上記（１）～（３）のいずれかに記載の炭化珪素基板において好ましくは、炭化珪素基板の直径は１００ｍｍ以上である。 (4) In the silicon carbide substrate according to any one of (1) to (3), preferably, the diameter of the silicon carbide substrate is 100 mm or more.
　（５）本開示に係る炭化珪素基板の製造方法は、主面を有する炭化珪素基板を準備する工程と、炭化珪素基板の主面を、金属触媒を含む研磨剤を用いて研磨する工程と、研磨する工程後に、炭化珪素基板を洗浄する工程とを備える。洗浄する工程は、炭化珪素基板を王水で洗浄する工程を含む。炭化珪素基板を研磨した後に王水で洗浄することにより、炭化珪素基板の被研磨面である主面に残存している金属触媒を除去することができる。したがって、主面上に形成されるエピ層の表面の面粗さを低減できる。 (5) A method for manufacturing a silicon carbide substrate according to the present disclosure includes a step of preparing a silicon carbide substrate having a main surface, a step of polishing the main surface of the silicon carbide substrate using an abrasive containing a metal catalyst, And a step of cleaning the silicon carbide substrate after the polishing step. The step of cleaning includes a step of cleaning the silicon carbide substrate with aqua regia. By cleaning the silicon carbide substrate with aqua regia after polishing, the metal catalyst remaining on the main surface, which is the surface to be polished, of the silicon carbide substrate can be removed. Therefore, the surface roughness of the surface of the epi layer formed on the main surface can be reduced.
　（６）上記炭化珪素基板の製造方法において好ましくは、研磨する工程において、研磨剤は、金属触媒として、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムからなる群から選ばれた少なくとも一種の金属元素を含む。 (6) Preferably in the method for producing a silicon carbide substrate, in the polishing step, the abrasive is at least selected from the group consisting of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium as a metal catalyst. Contains a kind of metal element.
　（７）上記（５）または（６）に記載の炭化珪素基板の製造方法において好ましくは、洗浄する工程は、炭化珪素基板を硫酸過水で洗浄する工程と、硫酸過水で洗浄する工程後に、炭化珪素基板をアンモニア過水で洗浄する工程とをさらに含む。アンモニア過水で洗浄する工程後に、王水で洗浄する工程を実施する。洗浄する工程はさらに、王水で洗浄する工程後に、炭化珪素基板を塩酸過水で洗浄する工程と、塩酸過水で洗浄する工程後に、炭化珪素基板をフッ酸で洗浄する工程とをさらに含む。これにより、炭化珪素基板の主面に残存している金属触媒および、金属触媒以外の金属を低減できる。この「金属触媒以外の金属」は、たとえばカリウム、ナトリウム、カルシウム、鉄、銅、アルミニウムおよび錫からなる群から選ばれた少なくとも一種の金属を含む。 (7) Preferably in the method for manufacturing a silicon carbide substrate according to (5) or (6) above, the step of cleaning is performed after the step of cleaning the silicon carbide substrate with sulfuric acid / hydrogen peroxide and the step of cleaning with sulfuric acid / hydrogen peroxide. And a step of cleaning the silicon carbide substrate with ammonia water. A step of washing with aqua regia is performed after the step of washing with ammonia overwater. The step of cleaning further includes a step of cleaning the silicon carbide substrate with hydrochloric acid overwater after the step of cleaning with aqua regia, and a step of cleaning the silicon carbide substrate with hydrofluoric acid after the step of cleaning with hydrochloric acid overwater. . Thereby, the metal catalyst remaining on the main surface of the silicon carbide substrate and metals other than the metal catalyst can be reduced. The “metal other than the metal catalyst” includes, for example, at least one metal selected from the group consisting of potassium, sodium, calcium, iron, copper, aluminum, and tin.
　（８）上記（７）に記載の炭化珪素基板の製造方法において好ましくは、硫酸過水で洗浄する工程、アンモニア過水で洗浄する工程、王水で洗浄する工程、塩酸過水で洗浄する工程およびフッ酸で洗浄する工程の各々において、処理時間を１５分以上とする。 (8) Preferably, in the method for producing a silicon carbide substrate according to (7) above, a step of washing with sulfuric acid / hydrogen peroxide, a step of washing with ammonia / hydrogen peroxide, a step of washing with aqua regia, a step of washing with hydrochloric acid / hydrogen peroxide. In each of the steps of washing with hydrofluoric acid, the treatment time is set to 15 minutes or more.
　（９）上記（５）または（６）に記載の炭化珪素基板の製造方法において好ましくは、洗浄する工程は、炭化珪素基板をアンモニア過水で洗浄する工程をさらに含む。アンモニア過水で洗浄する工程後に、炭化珪素基板を王水で洗浄する工程を実施する。これによれば、炭化珪素基板の主面に付着している有機物を低減できるとともに、炭化珪素基板の主面に残存している金属触媒および、金属触媒以外の金属を低減できる。 (9) Preferably, in the method for manufacturing a silicon carbide substrate according to (5) or (6) above, the step of cleaning further includes a step of cleaning the silicon carbide substrate with ammonia hydrogen peroxide. After the step of cleaning with ammonia overwater, a step of cleaning the silicon carbide substrate with aqua regia is performed. According to this, the organic substance adhering to the main surface of the silicon carbide substrate can be reduced, and the metal catalyst remaining on the main surface of the silicon carbide substrate and metals other than the metal catalyst can be reduced.
　（１０）上記（９）に記載の炭化珪素基板の製造方法において好ましくは、アンモニア過水で洗浄する工程および王水で洗浄する工程の各々において、処理時間を１５分以上とする。 (10) Preferably, in the method for manufacturing a silicon carbide substrate according to (9) above, the treatment time is set to 15 minutes or longer in each of the step of washing with ammonia perwater and the step of washing with aqua regia.
　（１１）上記（５）または（６）に記載の炭化珪素基板の製造方法において好ましくは、洗浄する工程は、炭化珪素基板を硫酸過水で洗浄する工程をさらに含む。硫酸過水で洗浄する工程後に、王水で洗浄する工程を実施する。洗浄する工程はさらに、王水で洗浄する工程後に、炭化珪素基板をフッ酸で洗浄する工程を含む。 (11) Preferably in the method for manufacturing a silicon carbide substrate according to (5) or (6) above, the cleaning step further includes a step of cleaning the silicon carbide substrate with sulfuric acid / hydrogen peroxide. After the step of washing with sulfuric acid / hydrogen peroxide, a step of washing with aqua regia is performed. The step of cleaning further includes a step of cleaning the silicon carbide substrate with hydrofluoric acid after the step of cleaning with aqua regia.
　（１２）上記（１１）に記載の炭化珪素基板の製造方法では、硫酸過水で洗浄する工程、王水で洗浄する工程およびフッ酸で洗浄する工程の各々において、処理時間を１５分以上とする。 (12) In the method for manufacturing a silicon carbide substrate according to (11), the treatment time is 15 minutes or more in each of the step of washing with sulfuric acid / hydrogen peroxide, the step of washing with aqua regia and the step of washing with hydrofluoric acid. To do.
　（１３）上記（５）～（１２）のいずれかに記載の炭化珪素基板の製造方法において好ましくは、王水で洗浄する工程において、王水と超純水とが混合された混合液における王水の体積濃度は５０％以上１００％以下である。 (13) Preferably, in the method for producing a silicon carbide substrate according to any one of (5) to (12) above, in the step of washing with aqua regia, the aqua regia in the mixed liquid in which aqua regia and ultrapure water are mixed is used. The volume concentration of water is 50% or more and 100% or less.
　（１４）上記（７）、（８）、（１１）および（１２）のいずれかに記載の炭化珪素基板の製造方法において好ましくは、硫酸過水で洗浄する工程において、硫酸過水が含む硫酸の体積は硫酸過水が含む超純水の体積の１倍以上５倍以下であり、硫酸過水が含む過酸化水素水の体積は硫酸過水が含む超純水の体積の１倍以上３倍以下である。 (14) In the method for producing a silicon carbide substrate according to any one of (7), (8), (11) and (12), preferably, the sulfuric acid contained in the sulfuric acid / hydrogen peroxide in the step of washing with sulfuric acid / hydrogen peroxide. Is 1 to 5 times the volume of the ultrapure water contained in the sulfuric acid hydrogen peroxide, and the volume of the hydrogen peroxide solution contained in the sulfuric acid hydrogen peroxide is 1 to 3 times the volume of the ultrapure water contained in the sulfuric acid hydrogen peroxide. Is less than double.
　（１５）上記（７）～（１０）のいずれかに記載の炭化珪素基板の製造工程において好ましくは、アンモニア過水で洗浄する工程において、アンモニア過水が含むアンモニア水溶液の体積はアンモニア過水が含む超純水の体積の１／１０倍以上１倍以下であり、アンモニア過水が含む過酸化水素水の体積はアンモニア過水が含む超純水の体積の１／１０倍以上１倍以下である。 (15) Preferably, in the step of manufacturing the silicon carbide substrate according to any one of (7) to (10) above, in the step of cleaning with ammonia perwater, the volume of the ammonia aqueous solution contained in the ammonia perwater is The volume of the ultrapure water contained is 1/10 times or more and 1 time or less, and the volume of the hydrogen peroxide solution contained in the ammonia perwater is 1/10 times or more and 1 time or less of the volume of the ultrapure water contained in the ammonia overwater. is there.
　（１６）上記（５）～（１５）のいずれかに記載の炭化珪素基板の製造方法において好ましくは、洗浄する工程では、炭化珪素基板の温度を４０℃以下とする。 (16) Preferably in the method for manufacturing a silicon carbide substrate according to any one of (5) to (15) above, the temperature of the silicon carbide substrate is set to 40 ° C. or lower in the cleaning step.
　[実施形態の詳細]
　以下、本開示の実施形態の具体例を図面を参照しつつ説明する。なお、以下の図面において同一または相当する部分には同一の参照番号を付し、その説明は繰り返さない。また、本明細書中においては、個別面を（）、集合面を｛｝でそれぞれ示す。また、負の指数については、結晶学上、”－”（バー）を数字の上に付けることになっているが、本明細書中では、数字の前に負の符号を付けている。 [Details of the embodiment]
Hereinafter, specific examples of the embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In the present specification, individual surfaces are indicated by (), and aggregate surfaces are indicated by {}. As for the negative index, “−” (bar) is added on the number in crystallography, but in the present specification, a negative sign is attached before the number.
　（実施の形態１）
　＜炭化珪素基板の構成＞
　まず、実施の形態１に係る炭化珪素基板の構成について説明する。図１は、実施の形態１に係る炭化珪素基板１０の構成を示す部分断面図である。 (Embodiment 1)
<Configuration of silicon carbide substrate>
First, the structure of the silicon carbide substrate according to the first embodiment will be described. FIG. 1 is a partial cross sectional view showing a configuration of silicon carbide substrate 10 according to the first embodiment.
　図１に示されるように、炭化珪素基板１０は、主面１０Ａを有している。炭化珪素基板１０は、たとえばポリタイプ４Ｈの六方晶炭化珪素単結晶からなる。炭化珪素基板１０はたとえば窒素などのｎ型不純物を含む。炭化珪素基板１０における不純物濃度はたとえば５．０×１０１８ｃｍ－３以上２．０×１０１９ｃｍ－３以下である。炭化珪素基板１０の直径は、たとえば１００ｍｍ以上（４インチ以上）であり、１５０ｍｍ以上（６インチ）であってもよい。 As shown in FIG. 1, silicon carbide substrate 10 has a main surface 10A. Silicon carbide substrate 10 is made of, for example, a polytype 4H hexagonal silicon carbide single crystal. Silicon carbide substrate 10 includes an n-type impurity such as nitrogen. The impurity concentration in silicon carbide substrate 10 is, for example, 5.0 × 10 18 cm −3 or more and 2.0 × 10 19 cm −3 or less. Silicon carbide substrate 10 has a diameter of, for example, 100 mm or more (4 inches or more), or 150 mm or more (6 inches).
　主面１０Ａにおける表面粗さ（Ｒａ）は０．１ｎｍ以下である。「表面粗さ（Ｒａ）」とは、ＪＩＳ　Ｂ０６０１に準拠して測定される値である。表面粗さ（Ｒａ）は、たとえば原子間力顕微鏡（ＡＦＭ：Atomic　Force　Microscope）を用いて測定することができる。 The surface roughness (Ra) of the main surface 10A is 0.1 nm or less. “Surface roughness (Ra)” is a value measured according to JIS B0601. The surface roughness (Ra) can be measured using, for example, an atomic force microscope (AFM).
　ＡＦＭとしては、たとえばＶｅｅｃｏ社製の「Ｄｉｍｅｎｓｉｏｎ３００」を用いることができる。また、上記ＡＦＭのカンチレバー（探針）としては、たとえば、Ｂｒｕｋｅｒ社製の型式「ＮＣＨＶ－１０Ｖ」を用いることができる。ＡＦＭの測定条件としては、一例として、測定モードをタッピングモードとし、かつ、タッピングモードでの測定領域を１０μｍ四方、ピッチを４０ｎｍおよび測定深さを１．０μｍとする。そして、タッピングモードでのサンプリングは、上記測定領域内での走査速度を１周期当たり５秒とし、１走査ラインあたりのデータ数を５１２ポイントとし、かつ、走査ライン数を５１２とする。また、カンチレバーの変位制御を１５．５０ｎｍに設定する。 As the AFM, for example, “Dimension 300” manufactured by Veeco can be used. As the AFM cantilever (probe), for example, model “NCHV-10V” manufactured by Bruker can be used. As an example of AFM measurement conditions, the measurement mode is the tapping mode, the measurement region in the tapping mode is 10 μm square, the pitch is 40 nm, and the measurement depth is 1.0 μm. In the sampling in the tapping mode, the scanning speed in the measurement area is set to 5 seconds per cycle, the number of data per scanning line is set to 512 points, and the number of scanning lines is set to 512. Also, the displacement control of the cantilever is set to 15.50 nm.
　主面１０Ａは、たとえば｛０００１｝面であってもよいし、｛０００１｝面に対して所定のオフ角（たとえば１０°以下のオフ角）を有する面であってもよい。 Main surface 10A may be a {0001} plane, for example, or a plane having a predetermined off angle (for example, an off angle of 10 ° or less) with respect to the {0001} plane.
　主面１０Ａにおけるバナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムのそれぞれの濃度は、いずれも１．０×１０６ａｔｏｍｓ／ｃｍ２以上であり、かつ、１．０×１０１２ａｔｏｍｓ／ｃｍ２以下である。より好ましくは、主面１０Ａにおけるカリウム、ナトリウム、カルシウム、鉄、銅、アルミニウムおよび錫のそれぞれの濃度は、いずれも１．０×１０１０ａｔｏｍｓ／ｃｍ２以下である。主面１０Ａにおける金属不純物の濃度は、ＩＣＰ－ＭＳ（Inductively　Coupled　Plasma　Mass　Spectrometry）により測定することができる。具体的には、たとえばＡｇｉｌｌｅｎｔ社製のＩＣＰ－ＭＳ７５００を用いることができる。 Each concentration of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium on main surface 10A is 1.0 × 10 6 atoms / cm 2 or more, and 1.0 × 10 12 atoms. / Cm 2 or less. More preferably, each concentration of potassium, sodium, calcium, iron, copper, aluminum, and tin on the main surface 10A is 1.0 × 10 10 atoms / cm 2 or less. The concentration of the metal impurity on the main surface 10A can be measured by ICP-MS (Inductively Coupled Plasma Mass Spectrometry). Specifically, for example, ICP-MS7500 manufactured by Agilent can be used.
　＜炭化珪素基板の製造方法＞
　実施の形態１に係る炭化珪素基板１０の製造方法について説明する。図２に示されるように、本実施の形態に係る炭化珪素基板１０の製造方法は、準備工程（Ｓ１０）、研磨工程（Ｓ２０）および洗浄工程（Ｓ３０）を含む。 <Method for producing silicon carbide substrate>
A method for manufacturing silicon carbide substrate 10 according to the first embodiment will be described. As shown in FIG. 2, the method for manufacturing silicon carbide substrate 10 according to the present embodiment includes a preparation step (S10), a polishing step (S20), and a cleaning step (S30).
　準備工程（Ｓ１０）では、単結晶炭化珪素インゴットから切り出された炭化珪素基板１０が準備される。図３に示されるように、本実施の形態に係る炭化珪素基板１０は、たとえばポリタイプ４Ｈの六方晶炭化珪素単結晶からなり、主面１１Ａを有している。 In the preparation step (S10), silicon carbide substrate 10 cut out from the single crystal silicon carbide ingot is prepared. As shown in FIG. 3, silicon carbide substrate 10 according to the present embodiment is made of, for example, a polytype 4H hexagonal silicon carbide single crystal and has a main surface 11A.
　研削工程（Ｓ２０）では、たとえば図４に示される研磨装置１００が用いられる。研磨装置１００には、たとえばＣＭＰ装置が用いられる。研磨工程（Ｓ２０）では、図５に示されるように、主面１１Ａが研磨されることにより、新たな主面１０Ａが形成される。図４に示されるように、実施の形態１で用いられる研磨装置１００は、基板保持部１０１と、回転定盤部１０４と、研磨布１０２と、研磨剤供給部１０８とを備えている。基板保持部１０１は、図示しないシャフトによって回転軸Ｃ２を中心に回転する加圧ヘッドを含む。回転定盤部１０４は、シャフト１０６によって回転軸Ｃ１を中心に回転する円板状部を含む。研磨布１０２は、回転定盤部１０４の上面に固着されている。回転定盤部１０４の上方には、研磨剤１１０を供給するための研磨剤供給部１０８が設けられている。 In the grinding step (S20), for example, a polishing apparatus 100 shown in FIG. 4 is used. As the polishing apparatus 100, for example, a CMP apparatus is used. In the polishing step (S20), as shown in FIG. 5, the main surface 11A is polished to form a new main surface 10A. As shown in FIG. 4, the polishing apparatus 100 used in the first embodiment includes a substrate holding unit 101, a rotating surface plate unit 104, a polishing cloth 102, and an abrasive supply unit 108. The substrate holding unit 101 includes a pressure head that rotates about a rotation axis C2 by a shaft (not shown). The rotating surface plate portion 104 includes a disk-like portion that rotates about the rotation axis C <b> 1 by the shaft 106. The polishing cloth 102 is fixed to the upper surface of the rotating surface plate portion 104. An abrasive supply unit 108 for supplying the abrasive 110 is provided above the rotating platen unit 104.
　研磨工程（Ｓ２０）を実施する際には、基板保持部１０１の加圧ヘッドの下面に炭化珪素基板１０を貼り付けて、主面１１Ａが研磨布１０２と対向するように配置する。そして、この加圧ヘッドを下降させて炭化珪素基板１０に所定の圧力を加える。次に、研磨剤供給部１０８から研磨剤１１０を研磨布１０２に供給しながら、基板保持部１０１と回転定盤部１０４とを同一方向（図４における矢印の方向）に回転させる。なお、基板保持部１０１と回転定盤部１０４とは逆方向に回転させてもよいし、一方を固定して他方を回転させてもよい。 When performing the polishing step (S20), the silicon carbide substrate 10 is attached to the lower surface of the pressure head of the substrate holding unit 101, and the main surface 11A is disposed so as to face the polishing cloth 102. Then, the pressure head is lowered and a predetermined pressure is applied to the silicon carbide substrate 10. Next, the substrate holding unit 101 and the rotating surface plate unit 104 are rotated in the same direction (the direction of the arrow in FIG. 4) while supplying the polishing agent 110 from the polishing agent supply unit 108 to the polishing pad 102. The substrate holding unit 101 and the rotating surface plate unit 104 may be rotated in the opposite directions, or one may be fixed and the other may be rotated.
　研磨工程（Ｓ２０）に用いられる研磨剤１１０は、砥粒と、酸化剤と、金属触媒とを含んでいる。砥粒は、表面粗さや加工変質層を低減させるために、炭化珪素よりも柔らかい材料である。砥粒として、たとえばコロイダルシリカ、ヒュームシリカ、アルミナ、ダイヤモンド等が用いられる。酸化剤は、主面１１Ａに酸化膜を形成させる。酸化剤として、たとえば過酸化水素水、次亜塩素酸ナトリウム、過炭素酸バリウム等が用いられる。 The polishing agent 110 used in the polishing step (S20) includes abrasive grains, an oxidizing agent, and a metal catalyst. The abrasive is a material softer than silicon carbide in order to reduce the surface roughness and the work-affected layer. As the abrasive grains, for example, colloidal silica, fume silica, alumina, diamond, or the like is used. The oxidizing agent forms an oxide film on the main surface 11A. As the oxidizing agent, for example, hydrogen peroxide, sodium hypochlorite, barium percarbonate or the like is used.
　金属触媒は、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムからなる群から選ばれた少なくとも一種の金属元素を含んでいる。金属触媒として、たとえばタングステン酸ナトリウム、バナジン酸ナトリウム、モリブデン酸ナトリウム等が用いられる。 The metal catalyst contains at least one metal element selected from the group consisting of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium. As the metal catalyst, for example, sodium tungstate, sodium vanadate, sodium molybdate and the like are used.
　研磨剤１１０は、ケミカル作用を増加させるためにｐＨ６以下またはｐＨ９．５以上であること好ましく、ｐＨ４以下、ｐＨ１０．５以上であることがより好ましい。研磨剤１１０のｐＨの制御は、塩酸、硝酸、硫酸、リン酸などの無機酸、ギ酸、酢酸、シュウ酸、クエン酸、リンゴ酸、酒石酸、コハク酸、フタル酸、フマル酸などの有機酸、ＫＯＨ、ＮａＯＨ、ＮＨ４ＯＨなどの無機アルカリ、コリン、アミン、ＴＭＡＨ（水酸化テトラメチルアンモニウム）などの有機アルカリ、およびそれらの塩を添加することで制御できる。 In order to increase the chemical action, the abrasive 110 is preferably pH 6 or lower or pH 9.5 or higher, more preferably pH 4 or lower and pH 10.5 or higher. The pH of the abrasive 110 is controlled by inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid, organic acids such as formic acid, acetic acid, oxalic acid, citric acid, malic acid, tartaric acid, succinic acid, phthalic acid and fumaric acid, It can be controlled by adding an inorganic alkali such as KOH, NaOH or NH 4 OH, an organic alkali such as choline, amine, TMAH (tetramethylammonium hydroxide), or a salt thereof.
　研磨工程（Ｓ２０）後の主面１０Ａの表面粗さ（Ｒａ）は、０．１ｎｍ以下である。主面１０Ａには、塵埃等の異物や、研磨工程（Ｓ２０）で用いられた研磨剤などが付着している場合がある。具体的には、主面１０Ａには、砥粒、有機物および、金属などが付着している場合がある。主面１０Ａに付着している金属は、たとえば、研磨剤に含まれる金属触媒や周辺環境に由来する。 The surface roughness (Ra) of the main surface 10A after the polishing step (S20) is 0.1 nm or less. The main surface 10A may have foreign matters such as dust or the abrasive used in the polishing step (S20) attached thereto. Specifically, abrasive grains, organic substances, metals, and the like may adhere to the main surface 10A. The metal adhering to 10 A of main surfaces originates in the metal catalyst contained in an abrasive | polishing agent and surrounding environment, for example.
　次に、洗浄工程（Ｓ３０：図２）が実施される。図６に示されるように、実施の形態１で用いられる洗浄装置１２０は、洗浄処理層１２２と、ポンプ１２４と、フィルタ１２６と、ヒーター１２８とを備える。洗浄処理は、洗浄液１３０に満たされた洗浄処理層１２２に炭化珪素基板１０を一定時間浸漬することにより行なわれる。浸漬された主面１０Ａに付着している塵埃等の異物、有機物および金属の少なくとも一部は洗浄液１３０に溶解し、除去される。洗浄液１３０は、ポンプ１２４により常時循環し、フィルタ１２６により濾過される。また、洗浄液１３０は、ヒーター１２８を用いた温度制御が行なわれることによって所望の温度に保たれている。 Next, a cleaning process (S30: FIG. 2) is performed. As shown in FIG. 6, the cleaning device 120 used in the first embodiment includes a cleaning processing layer 122, a pump 124, a filter 126, and a heater 128. The cleaning process is performed by immersing silicon carbide substrate 10 in cleaning process layer 122 filled with cleaning liquid 130 for a certain period of time. At least a part of foreign matter such as dust, organic matter and metal adhering to the immersed main surface 10A is dissolved in the cleaning liquid 130 and removed. The cleaning liquid 130 is constantly circulated by the pump 124 and filtered by the filter 126. The cleaning liquid 130 is maintained at a desired temperature by performing temperature control using the heater 128.
　図７に示されるように、洗浄工程（Ｓ３０）は、たとえば硫酸過水洗浄（Ｓ３１）、アンモニア過水洗浄（Ｓ３２）、王水洗浄（Ｓ３３）、塩酸過水洗浄（Ｓ３４）、フッ酸洗浄（Ｓ３５）の順に実施される複数の工程を含む。それぞれの洗浄工程の終了後には、超純水洗浄工程が実施されてもよい。主面１０Ａに残存している洗浄液等を洗い流すためである。超純水としては、たとえば、電気抵抗率が１５ＭΩ・ｃｍ以上であり、有機物量（ＴＯＣ：Total　Organ　Carbon）が１００ｐｐｂ未満であり、かつ残存シリカが１０ｐｐｂ未満である水を使用することができる。以降の工程で用いられる超純水についても同様である。 As shown in FIG. 7, the cleaning step (S30) includes, for example, sulfuric acid / aqueous cleaning (S31), ammonia / aqueous cleaning (S32), aqua regia cleaning (S33), hydrochloric acid / overwater cleaning (S34), and hydrofluoric acid cleaning. A plurality of steps are performed in the order of (S35). After completion of each cleaning process, an ultrapure water cleaning process may be performed. This is to wash away the cleaning liquid remaining on the main surface 10A. As ultrapure water, for example, water having an electrical resistivity of 15 MΩ · cm or more, an organic substance (TOC: Total Organ Carbon) of less than 100 ppb, and a residual silica of less than 10 ppb can be used. The same applies to ultrapure water used in the subsequent steps.
　なお、硫酸過水洗浄工程の前に、アルカリ洗浄工程を実施してもよい。アルカリ洗浄工程では、たとえばＴＭＡＨおよび界面活性剤によって、研磨工程（Ｓ２０）において主面１０Ａに付着したコロイダルシリカなどの砥粒が除去される。 In addition, you may implement an alkali washing | cleaning process before a sulfuric acid perwater washing | cleaning process. In the alkali cleaning step, for example, TMAH and a surfactant remove abrasive grains such as colloidal silica attached to the main surface 10A in the polishing step (S20).
　硫酸過水洗浄工程（Ｓ３１）では、硫酸過水によって主面１０Ａに付着した有機物などが除去される。硫酸過水は、硫酸と、過酸化水素水と、超純水とが混合された溶液である。硫酸としては、たとえば質量百分率濃度が９８％の濃硫酸を使用することができる。過酸化水素水としては、たとえば質量百分率濃度が３０％の過酸化水素水を用いることができる。以降の工程で用いられる過酸化水素水についても同様である。 In the sulfuric acid / hydrogen peroxide washing step (S31), organic substances adhering to the main surface 10A are removed by sulfuric acid / hydrogen peroxide. Sulfuric acid / hydrogen peroxide is a solution in which sulfuric acid, hydrogen peroxide water, and ultrapure water are mixed. As sulfuric acid, for example, concentrated sulfuric acid having a mass percentage concentration of 98% can be used. As the hydrogen peroxide solution, for example, a hydrogen peroxide solution having a mass percentage concentration of 30% can be used. The same applies to the hydrogen peroxide solution used in the subsequent steps.
　硫酸過水が含む、硫酸と、過酸化水素水と、超純水との体積比率は、たとえば１（硫酸）：１（過酸化水素水）：１（超純水）である。好ましくは、硫酸と、過酸化水素水と、超純水との体積比率は、１（硫酸）：１（過酸化水素水）：１（超純水）から５（硫酸）：３（過酸化水素水）：１（超純水）である。言い換えれば、硫酸の体積は超純水の体積の１倍以上５倍以下である。また、過酸化水素水の体積は超純水の体積の１倍以上３倍以下である。 The volume ratio of sulfuric acid, hydrogen peroxide water, and ultrapure water contained in the sulfuric acid perwater is, for example, 1 (sulfuric acid): 1 (hydrogen peroxide water): 1 (ultra pure water). Preferably, the volume ratio of sulfuric acid, hydrogen peroxide solution, and ultrapure water is 1 (sulfuric acid): 1 (hydrogen peroxide solution): 1 (ultrapure water) to 5 (sulfuric acid): 3 (peroxidation) Hydrogen water): 1 (ultra pure water). In other words, the volume of sulfuric acid is 1 to 5 times the volume of ultrapure water. Moreover, the volume of hydrogen peroxide water is 1 to 3 times the volume of ultrapure water.
　次に、アンモニア過水洗浄工程（Ｓ３２）では、アンモニア過水によって、主面１０Ａに付着した有機物が除去される。アンモニア過水は、アンモニア水溶液と、過酸化水素水と、超純水とが混合された溶液である。アンモニア水溶液としては、たとえば質量百分率濃度が２８％のアンモニア水溶液を使用することができる。 Next, in the ammonia overwater washing step (S32), the organic substances adhering to the main surface 10A are removed by the ammonia overwater. Ammonia overwater is a solution in which an aqueous ammonia solution, hydrogen peroxide solution, and ultrapure water are mixed. As the aqueous ammonia solution, for example, an aqueous ammonia solution having a mass percentage concentration of 28% can be used.
　アンモニア過水が含む、アンモニア水溶液と、過酸化水素水と、超純水との体積比率は、たとえば１（アンモニア水溶液）：１（過酸化水素水）：１０（超純水）：である。好ましくは、アンモニア水溶液と、過酸化水素水と、超純水との体積比率は、１（アンモニア水溶液）：１（過酸化水素水）：１０（超純水）から１（アンモニア水溶液）：１（過酸化水素水）：１（超純水）である。言い換えれば、アンモニア水溶液の体積は超純水の体積の１／１０倍以上１倍以下である。また、過酸化水素水の体積は超純水の体積の１／１０倍以上１倍以下である。 The volume ratio of the aqueous ammonia solution, the hydrogen peroxide solution, and the ultrapure water contained in the ammonia overwater is, for example, 1 (aqueous ammonia solution): 1 (hydrogen peroxide solution): 10 (ultrapure water): Preferably, the volume ratio of the aqueous ammonia solution, the hydrogen peroxide solution, and the ultrapure water is 1 (ammonia aqueous solution): 1 (hydrogen peroxide solution): 10 (ultrapure water) to 1 (ammonia aqueous solution): 1 (Hydrogen peroxide solution): 1 (ultra pure water). In other words, the volume of the aqueous ammonia solution is 1/10 to 1 times the volume of ultrapure water. Moreover, the volume of hydrogen peroxide water is 1/10 times or more and 1 time or less of the volume of ultrapure water.
　次に、王水洗浄工程（Ｓ３３）では、王水によって主面１０Ａに残存している金属触媒に由来する金属の少なくとも一部が除去される。つまり、主面１０Ａに残存している金属が低減される。王水は、塩酸と硝酸とが混合された溶液である。本明細書では、塩酸と硝酸とが混合された溶液だけでなく、当該溶液と超純水との混合液も「王水」と呼ぶ。本実施の形態１では、王水または、王水が含む、塩酸と、硝酸と、超純水との体積比率は、たとえば３（塩酸）：１（硝酸）：０（超純水）である。好ましくは、塩酸と、硝酸と、超純水との体積比率は、３（塩酸）：１（硝酸）：０（超純水）から３（塩酸）：１（硝酸）：２（超純水）である。好ましくは、王水（塩酸と硝酸との混合溶液）と超純水とが混合された混合液における当該王水の体積濃度は５０％以上１００％以下である。 Next, in the aqua regia washing step (S33), at least a part of the metal derived from the metal catalyst remaining on the main surface 10A is removed by the aqua regia. That is, the metal remaining on the main surface 10A is reduced. Aqua regia is a solution in which hydrochloric acid and nitric acid are mixed. In this specification, not only a solution in which hydrochloric acid and nitric acid are mixed, but also a mixed solution of the solution and ultrapure water is referred to as “aqua regia”. In the first embodiment, the volume ratio of aqua regia or aqua regia contained in hydrochloric acid, nitric acid, and ultrapure water is, for example, 3 (hydrochloric acid): 1 (nitric acid): 0 (ultra pure water). . Preferably, the volume ratio of hydrochloric acid, nitric acid, and ultrapure water is 3 (hydrochloric acid): 1 (nitric acid): 0 (ultrapure water) to 3 (hydrochloric acid): 1 (nitric acid): 2 (ultrapure water). ). Preferably, the volume concentration of the aqua regia in a mixed solution in which aqua regia (mixed solution of hydrochloric acid and nitric acid) and ultrapure water are mixed is 50% or more and 100% or less.
　次に、塩酸過水洗浄工程（Ｓ３４）では、塩酸過水によって主面１０Ａの残存している金属触媒由来以外の金属の少なくとも一部が除去される、塩酸過水は、塩酸と、過酸化水素水と、超純水とが混合された溶液である。塩酸としては、たとえば質量百分率濃度が９８％の濃塩酸を使用することができる。 Next, in the hydrochloric acid overwater washing step (S34), at least a part of the metal other than the metal catalyst remaining on the main surface 10A is removed by hydrochloric acid overwater. This is a solution in which hydrogen water and ultrapure water are mixed. As hydrochloric acid, for example, concentrated hydrochloric acid having a mass percentage concentration of 98% can be used.
　塩酸過水が含む、塩酸と、過酸化水素水と、超純水との体積比率は、たとえば１（塩酸）：１（過酸化水素水）：１０（超純水）である。好ましくは、塩酸と、過酸化水素水と、超純水との体積比率は、１（塩酸）：１（過酸化水素水）：１０（超純水）から１（塩酸）：１（過酸化水素水）：５（超純水）である。言い換えれば、塩酸の体積は超純水の体積の１／１０倍以上１／５倍以下である。また、過酸化水素水の体積は超純水の体積の１／１０倍以上１／５倍以下である。 The volume ratio of hydrochloric acid, hydrogen peroxide solution, and ultrapure water contained in the hydrochloric acid overwater is, for example, 1 (hydrochloric acid): 1 (hydrogen peroxide solution): 10 (ultrapure water). Preferably, the volume ratio of hydrochloric acid, hydrogen peroxide solution, and ultrapure water is 1 (hydrochloric acid): 1 (hydrogen peroxide solution): 10 (ultrapure water) to 1 (hydrochloric acid): 1 (peroxidation). Hydrogen water): 5 (ultra pure water). In other words, the volume of hydrochloric acid is 1/10 to 1/5 times the volume of ultrapure water. The volume of the hydrogen peroxide solution is 1/10 to 1/5 times the volume of ultrapure water.
　次に、フッ酸洗浄工程（Ｓ３５）では、フッ酸によりシリコン酸化膜が除去される。フッ酸と超純水とが混合された混合液におけるフッ酸の濃度は、たとえば３０％である。好ましくは、混合液におけるフッ酸の濃度は２０％以上５０％以下である。 Next, in the hydrofluoric acid cleaning step (S35), the silicon oxide film is removed by hydrofluoric acid. The concentration of hydrofluoric acid in the mixed liquid in which hydrofluoric acid and ultrapure water are mixed is, for example, 30%. Preferably, the concentration of hydrofluoric acid in the mixed solution is 20% or more and 50% or less.
　以上の工程（Ｓ３１）～工程（Ｓ３５）の各々の処理時間はいずれも、たとえば３０分である。当該処理時間は、好ましくは１５分以上であり、より好ましくは３０分以上である。 The processing time of each of the above steps (S31) to (S35) is, for example, 30 minutes. The treatment time is preferably 15 minutes or longer, more preferably 30 minutes or longer.
　以上の工程（Ｓ３１）～工程（Ｓ３５）の各々において、炭化珪素基板１０の温度はたとえば室温である。各工程において炭化珪素基板１０の温度は４０℃以下とすることが好ましい。 In each of the above steps (S31) to (S35), the temperature of silicon carbide substrate 10 is, for example, room temperature. In each step, the temperature of silicon carbide substrate 10 is preferably 40 ° C. or lower.
　以上のように、洗浄工程（Ｓ３０）によって金属濃度が低減された主面１０Ａを有する炭化珪素基板１０（図１）が得られる。 As described above, silicon carbide substrate 10 (FIG. 1) having main surface 10A in which the metal concentration is reduced is obtained by the cleaning step (S30).
　本実施の形態に係る炭化珪素基板１０の製造方法における洗浄工程（Ｓ３０）は上記に限られない。以下に、洗浄工程（Ｓ３０）の変形例が示される。 The cleaning step (S30) in the method for manufacturing silicon carbide substrate 10 according to the present embodiment is not limited to the above. Below, the modification of a washing | cleaning process (S30) is shown.
　（変形例１）
　図８に示されるように、洗浄工程は、たとえばアンモニア過水洗浄（Ｓ３２）。王水洗浄（Ｓ３３）の順に実施される複数の工程を含む。それぞれの洗浄工程終了後には、超純水洗浄工程が実施されてもよい。なお、硫酸過水洗浄工程の前に、アルカリ洗浄工程が実施されてもよい。 (Modification 1)
As shown in FIG. 8, the cleaning step is, for example, ammonia overwater cleaning (S32). It includes a plurality of steps performed in the order of aqua regia cleaning (S33). After each cleaning step, an ultrapure water cleaning step may be performed. In addition, an alkali washing | cleaning process may be implemented before a sulfuric acid hydrogen peroxide washing | cleaning process.
　（変形例２）
　図９に示されるように、洗浄工程は、たとえば硫酸過水洗浄（Ｓ３１）、アンモニア過水洗浄（Ｓ３２）、王水洗浄（Ｓ３３）およびフッ酸洗浄（Ｓ３５）の順に実施される複数の工程を含む、それぞれの洗浄工程終了後には、超純水洗浄工程が実施されてもよい。なお、硫酸過水洗浄工程の前に、アルカリ洗浄工程が実施されてもよい。 (Modification 2)
As shown in FIG. 9, the cleaning process is performed in the order of, for example, sulfuric acid / hydrogen peroxide cleaning (S31), ammonia / hydrogen peroxide cleaning (S32), aqua regia cleaning (S33), and hydrofluoric acid cleaning (S35). After each cleaning process including the above, an ultrapure water cleaning process may be performed. In addition, an alkali washing process may be implemented before a sulfuric acid perwater washing process.
　主面１０Ａに存在する金属濃度と、炭化珪素基板１０の洗浄方法との関係が、表１に示される。 Table 1 shows the relationship between the metal concentration present on main surface 10A and the method for cleaning silicon carbide substrate 10.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　サンプル１～３の各々に係る炭化珪素基板１０は、実施の形態１に係る製造方法によって製造された。 The silicon carbide substrate 10 according to each of samples 1 to 3 was manufactured by the manufacturing method according to the first embodiment.
　サンプル１～３の各々に係る洗浄工程（Ｓ３０）の詳細が以下に述べられる。最初に硫酸過水洗浄工程（Ｓ３１）が実施された。硫酸過水が含む、硫酸と、過酸化水素水と、超純水との体積比率は、１（硫酸）：１（過酸化水素水）：１（超純水）である。硫酸過水洗浄工程（Ｓ３１）における処理時間は３０分であり、硫酸過水の液温は室温であった。 Details of the cleaning step (S30) relating to each of samples 1 to 3 will be described below. First, the sulfuric acid / hydrogen peroxide washing step (S31) was performed. The volume ratio of sulfuric acid, hydrogen peroxide solution, and ultrapure water contained in the sulfuric acid / hydrogen peroxide is 1 (sulfuric acid): 1 (hydrogen peroxide solution): 1 (ultrapure water). The treatment time in the sulfuric acid / hydrogen peroxide washing step (S31) was 30 minutes, and the liquid temperature of sulfuric acid / hydrogen peroxide was room temperature.
　次にアンモニア過水洗浄工程（Ｓ３２）が実施された。アンモニア過水が含む、アンモニア水溶液と、過酸化水素水と、超純水との体積比率は、１（アンモニア水溶液）：１（過酸化水素水）：１０（超純水）：である。アンモニア過水洗浄工程（Ｓ３２）における処理時間は３０分であり、アンモニア過水の液温は室温であった。 Next, an ammonia overwater washing step (S32) was performed. The volume ratio of the aqueous ammonia solution, the hydrogen peroxide solution, and the ultrapure water contained in the ammonia overwater is 1 (aqueous ammonia solution): 1 (hydrogen peroxide solution): 10 (ultrapure water): The treatment time in the ammonia overwater washing step (S32) was 30 minutes, and the liquid temperature of the ammonia overwater was room temperature.
　次に王水洗浄工程（Ｓ３３）が実施された。王水が含む、塩酸と、硝酸と、超純水との体積比率は、３（塩酸）：１（硝酸）：０（超純水）である。王水洗浄工程（Ｓ３３）における処理時間は３０分であり、王水の液温は室温であった。 Next, the aqua regia washing step (S33) was carried out. The volume ratio of hydrochloric acid, nitric acid and ultrapure water contained in aqua regia is 3 (hydrochloric acid): 1 (nitric acid): 0 (ultrapure water). The treatment time in the aqua regia washing step (S33) was 30 minutes, and the aqua regia liquid temperature was room temperature.
　次に塩酸過水洗浄工程（Ｓ３４）が実施された。塩酸過水が含む、塩酸と、過酸化水素水と、超純水との体積比率は、１（塩酸）：１（過酸化水素水）：１０（超純水）である。塩酸過水洗浄工程（Ｓ３４）における処理時間は３０分であり、王水の液温は室温であった。 Next, a hydrochloric acid overwater washing step (S34) was performed. The volume ratio of hydrochloric acid, hydrogen peroxide solution, and ultrapure water contained in the hydrochloric acid overwater is 1 (hydrochloric acid): 1 (hydrogen peroxide solution): 10 (ultrapure water). The treatment time in the hydrochloric acid overwater washing step (S34) was 30 minutes, and the aqua regia liquid temperature was room temperature.
　次にフッ酸洗浄工程（Ｓ３５）が実施された。フッ酸と超純水とが混合された混合液におけるフッ酸の濃度は、３０％である。フッ酸洗浄工程（Ｓ３５）における処理時間は３０分であり、フッ酸の液温は室温であった。つまり、サンプル１～３の各々に係る洗浄工程（Ｓ３０）において、洗浄中の炭化珪素基板１０の温度は４０℃以下であった。本洗浄工程は全て室温で実施される。その理由は以下の通りである。炭化珪素は化学的に不活性であるため、表面を酸化、リフトオフするために長い時間を要する。従来のいわゆるＲＣＡ洗浄のような洗浄では、高温の硫酸過水や塩酸過水が用いられる。しかしながら、炭化珪素の洗浄において高温の硫酸過水や塩酸過水が用いられると、洗浄処理の途中で硫酸過水や塩酸過水が抜けてしまい洗浄効果が低減する。そのため、炭化珪素は室温で洗浄されることが好ましい。 Next, a hydrofluoric acid cleaning step (S35) was performed. The concentration of hydrofluoric acid in the mixed liquid in which hydrofluoric acid and ultrapure water are mixed is 30%. The treatment time in the hydrofluoric acid cleaning step (S35) was 30 minutes, and the liquid temperature of hydrofluoric acid was room temperature. That is, in the cleaning step (S30) according to each of samples 1 to 3, the temperature of silicon carbide substrate 10 during cleaning was 40 ° C. or lower. All the cleaning steps are performed at room temperature. The reason is as follows. Since silicon carbide is chemically inert, it takes a long time to oxidize and lift off the surface. In conventional cleaning such as so-called RCA cleaning, high-temperature sulfuric acid / hydrogen peroxide / water is used. However, when high-temperature sulfuric acid / hydrochloric acid / hydrogen peroxide is used in cleaning silicon carbide, sulfuric acid / hydrochloric acid / hydrogen peroxide is removed during the cleaning process, and the cleaning effect is reduced. Therefore, silicon carbide is preferably washed at room temperature.
　（測定方法）
　サンプル１～３の各々について、主面１０Ａに存在する金属濃度が測定された。サンプル１については、バナジウム（Ｖ）、タングステン（Ｗ）、モリブデン（Ｍｏ）、白金（Ｐｔ）、ニッケル（Ｎｉ）、チタン（Ｔｉ）、クロム（Ｃｒ）、鉄（Ｆｅ）、銅（Ｃｕ）、亜鉛（Ｚｎ）、アルミニウム（Ａｌ）、ナトリウム（Ｎａ）、カルシウム（Ｃａ）、カリウム（Ｋ）および錫（Ｓｎ）の濃度が測定された。サンプル２およびサンプル３については、バナジウム（Ｖ）および亜鉛（Ｚｎ）の濃度が測定された。金属濃度の測定は、ＩＣＰ－ＭＳにより行なわれた。サンプル１に係る主面１０Ａの金属濃度の測定結果を表２および表３に示す。表２は、主面１０Ａに存在する金属触媒の濃度の測定結果である。 (Measuring method)
For each of Samples 1 to 3, the concentration of metal present on main surface 10A was measured. For sample 1, vanadium (V), tungsten (W), molybdenum (Mo), platinum (Pt), nickel (Ni), titanium (Ti), chromium (Cr), iron (Fe), copper (Cu), The concentrations of zinc (Zn), aluminum (Al), sodium (Na), calcium (Ca), potassium (K) and tin (Sn) were measured. For samples 2 and 3, the concentrations of vanadium (V) and zinc (Zn) were measured. The metal concentration was measured by ICP-MS. Tables 2 and 3 show the measurement results of the metal concentration of the main surface 10A according to Sample 1. Table 2 shows the measurement results of the concentration of the metal catalyst present on the main surface 10A.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示されるように、サンプル１に係る主面１０Ａにおいて、金属濃度は、バナジウム（Ｖ）、タングステン（Ｗ）、モリブデン（Ｍｏ）、白金（Ｐｔ）、ニッケル（Ｎｉ）、チタン（Ｔｉ）およびクロム（Ｃｒ）のいずれにおいても、１×１０１２ａｔｏｍｓ／ｃｍ２以下の値を示している。サンプル２の主面１０Ａおよびサンプル３の主面１０Ａに存在するバナジウム（Ｖ）の濃度は、それぞれ７２×１０9ａｔｏｍｓ／ｃｍ２および１６×１０9ａｔｏｍｓ／ｃｍ２であった。 As shown in Table 2, in the main surface 10A according to Sample 1, the metal concentration is vanadium (V), tungsten (W), molybdenum (Mo), platinum (Pt), nickel (Ni), titanium (Ti). Both chromium and chromium (Cr) show values of 1 × 10 12 atoms / cm 2 or less. The concentrations of vanadium (V) present on the main surface 10A of sample 2 and the main surface 10A of sample 3 were 72 × 10 9 atoms / cm 2 and 16 × 10 9 atoms / cm 2 , respectively.
　表３は、主面１０Ａに存在する金属触媒以外の金属濃度の測定結果である。なお、表３において、「ＮＤ」とは検出下限値（１×１０７ａｔｏｍｓ／ｃｍ２）よりも低いため、検出されなかったことを示す。 Table 3 shows measurement results of metal concentrations other than the metal catalyst present on the main surface 10A. In Table 3, “ND” is lower than the detection lower limit (1 × 10 7 atoms / cm 2 ), and thus indicates that it was not detected.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３に示されるように、サンプル１に係る主面１０Ａにおいて、金属触媒以外の金属として、鉄（Ｆｅ）、銅（Ｃｕ）、亜鉛（Ｚｎ）、アルミニウム（Ａｌ）、ナトリウム（Ｎａ）、カルシウム（Ｃａ）、カリウム（Ｋ）および錫（Ｓｎ）が確認された。しかしながら、サンプル１に係る主面１０Ａにおけるこれらの金属の濃度はいずれも、１×１０１１ａｔｏｍｓ／ｃｍ２を下回っていることが確認された。サンプル２の主面１０Ａおよびサンプル３の主面１０Ａに存在する亜鉛（Ｚｎ）の濃度は、それぞれ１６×１０9ａｔｏｍｓ／ｃｍ２および２１×１０9ａｔｏｍｓ／ｃｍ２であった。 As shown in Table 3, in the main surface 10A according to Sample 1, as a metal other than the metal catalyst, iron (Fe), copper (Cu), zinc (Zn), aluminum (Al), sodium (Na), calcium (Ca), potassium (K) and tin (Sn) were confirmed. However, it was confirmed that the concentrations of these metals on the main surface 10A according to the sample 1 were all lower than 1 × 10 11 atoms / cm 2 . The concentrations of zinc (Zn) present on the main surface 10A of sample 2 and the main surface 10A of sample 3 were 16 × 10 9 atoms / cm 2 and 21 × 10 9 atoms / cm 2 , respectively.
　今回開示された実施の形態はすべての点で例示であって、制限的なものではないと考えられるべきである。本発明の範囲は上記した実施の形態ではなく請求の範囲によって示され、請求の範囲と均等の意味、および範囲内でのすべての変更が含まれることが意図される。 It should be considered that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.
　１０　炭化珪素基板、１０Ａ　主表面、１１Ａ　主面、２０　エピタキシャル層、３０　金属不純物、１００　研磨装置、１０１　基板保持部、１０２　研磨布、１０４　回転定盤部、１０６　シャフト、１０８　研磨剤供給部、１１０　研磨剤、１２０　洗浄装置、１２２　洗浄処理層、１２４　ポンプ、１２６　フィルタ、１２８　ヒーター。 10 silicon carbide substrate, 10A main surface, 11A main surface, 20 epitaxial layer, 30 metal impurities, 100 polishing apparatus, 101 substrate holding unit, 102 polishing cloth, 104 rotating surface plate unit, 106 shaft, 108 abrasive supply unit, 110 Abrasive, 120 cleaning device, 122 cleaning layer, 124 pump, 126 filter, 128 heater.

Claims (16)

  1. 　主面を有する炭化珪素基板であって、
    　前記主面の表面粗さ（Ｒａ）が０．１ｎｍ以下であり、かつ、前記主面において、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムのそれぞれの濃度はいずれも、１．０×１０１２ａｔｏｍｓ／ｃｍ２以下である、炭化珪素基板。     A silicon carbide substrate having a main surface,
    The main surface has a surface roughness (Ra) of 0.1 nm or less, and each of the concentrations of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium and chromium in the main surface is 1. The silicon carbide substrate which is 0 × 10 12 atoms / cm 2 or less.
  2. 　前記主面において、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムのそれぞれの濃度はいずれも、２．０×１０１１ａｔｏｍｓ／ｃｍ２以下である、請求項１に記載の炭化珪素基板。 2. The silicon carbide according to claim 1, wherein in the main surface, each concentration of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium, and chromium is 2.0 × 10 11 atoms / cm 2 or less. substrate.
  3. 　前記主面において、カリウム、ナトリウム、カルシウム、鉄、銅、アルミニウムおよび錫のそれぞれの濃度はいずれも、１．０×１０１０ａｔｏｍｓ／ｃｍ２以下である、請求項１または請求項２に記載の炭化珪素基板。 In the main surface, potassium, sodium, calcium, iron, copper, any respective concentrations of aluminum and tin is 1.0 × 10 10 atoms / cm 2 or less, according to claim 1 or claim 2 Silicon carbide substrate.
  4. 　前記炭化珪素基板の直径は１００ｍｍ以上である、請求項１から請求項３のいずれか１項に記載の炭化珪素基板。 The silicon carbide substrate according to any one of claims 1 to 3, wherein a diameter of the silicon carbide substrate is 100 mm or more.
  5. 　主面を有する炭化珪素基板を準備する工程と、
    　前記炭化珪素基板の前記主面を、金属触媒を含む研磨剤を用いて研磨する工程と、
    　前記研磨する工程後に、前記炭化珪素基板を洗浄する工程とを備え、
    　前記洗浄する工程は、前記炭化珪素基板を王水で洗浄する工程を含む、炭化珪素基板の製造方法。     Preparing a silicon carbide substrate having a main surface;
    Polishing the main surface of the silicon carbide substrate with an abrasive containing a metal catalyst;
    And after the polishing step, cleaning the silicon carbide substrate,
    The step of cleaning includes a step of cleaning the silicon carbide substrate with aqua regia.
  6. 　前記研磨する工程において、前記研磨剤は、前記金属触媒として、バナジウム、タングステン、モリブデン、白金、ニッケル、チタン、ジルコニウムおよびクロムからなる群から選ばれた少なくとも一種の金属元素を含む、請求項５に記載の炭化珪素基板の製造方法。 In the polishing step, the abrasive contains at least one metal element selected from the group consisting of vanadium, tungsten, molybdenum, platinum, nickel, titanium, zirconium, and chromium as the metal catalyst. The manufacturing method of the silicon carbide substrate of description.
  7. 　前記洗浄する工程は、
    　前記炭化珪素基板を硫酸過水で洗浄する工程と、
    　前記硫酸過水で洗浄する工程後に、前記炭化珪素基板をアンモニア過水で洗浄する工程とをさらに含み、
    　前記アンモニア過水で洗浄する工程後に、前記王水で洗浄する工程を実施し、
    　前記洗浄する工程はさらに、
    　前記王水で洗浄する工程後に、前記炭化珪素基板を塩酸過水で洗浄する工程と、
    　前記塩酸過水で洗浄する工程後に、前記炭化珪素基板をフッ酸で洗浄する工程とを含む、請求項５または請求項６に記載の炭化珪素基板の製造方法。     The washing step includes
    Washing the silicon carbide substrate with sulfuric acid / hydrogen peroxide;
    After the step of washing with sulfuric acid / hydrogen peroxide, further comprising washing the silicon carbide substrate with ammonia / hydrogen peroxide;
    After the step of washing with ammonia overwater, carrying out the step of washing with the aqua regia,
    The washing step further includes
    After the step of cleaning with aqua regia, cleaning the silicon carbide substrate with hydrochloric acid over water;
    The method for manufacturing a silicon carbide substrate according to claim 5, further comprising a step of cleaning the silicon carbide substrate with hydrofluoric acid after the step of cleaning with the hydrochloric acid / hydrogen peroxide solution.
  8. 　前記硫酸過水で洗浄する工程、前記アンモニア過水で洗浄する工程、前記王水で洗浄する工程、前記塩酸過水で洗浄する工程、および前記フッ酸で洗浄する工程の各々において、処理時間を１５分以上とする、請求項７に記載の炭化珪素基板の製造方法。 In each of the step of washing with sulfuric acid / hydrogen peroxide, the step of washing with ammonia / hydrogen peroxide, the step of washing with aqua regia, the step of washing with hydrochloric acid / hydrogen peroxide, and the step of washing with hydrofluoric acid, treatment time is set. The method for manufacturing a silicon carbide substrate according to claim 7, wherein the method is made for 15 minutes or more.
  9. 　前記洗浄する工程は、前記炭化珪素基板をアンモニア過水で洗浄する工程をさらに含み、
    　前記アンモニア過水で洗浄する工程後に、前記炭化珪素基板を王水で洗浄する工程を実施する、請求項５または請求項６に記載の炭化珪素基板の製造方法。     The step of cleaning further includes a step of cleaning the silicon carbide substrate with ammonia perwater,
    The method for manufacturing a silicon carbide substrate according to claim 5 or 6, wherein a step of cleaning the silicon carbide substrate with aqua regia is performed after the step of cleaning with the ammonia-overwater.
  10. 　前記アンモニア過水で洗浄する工程および前記王水で洗浄する工程の各々において、処理時間を１５分以上とする、請求項９に記載の炭化珪素基板の製造方法。 10. The method for manufacturing a silicon carbide substrate according to claim 9, wherein a treatment time is set to 15 minutes or longer in each of the step of washing with ammonia overwater and the step of washing with aqua regia.
  11. 　前記洗浄する工程は、
    　前記炭化珪素基板を硫酸過水で洗浄する工程をさらに含み、
    　前記硫酸過水で洗浄する工程後に、前記王水で洗浄する工程を実施し、
    　前記洗浄する工程は、前記王水で洗浄する工程後に、前記炭化珪素基板をフッ酸で洗浄する工程をさらに含む、請求項５または請求項６に記載の炭化珪素基板の製造方法。     The washing step includes
    Further comprising washing the silicon carbide substrate with sulfuric acid / hydrogen peroxide;
    After the step of washing with sulfuric acid / hydrogen peroxide, carrying out the step of washing with the aqua regia,
    The method for manufacturing a silicon carbide substrate according to claim 5, wherein the cleaning step further includes a step of cleaning the silicon carbide substrate with hydrofluoric acid after the step of cleaning with the aqua regia.
  12. 　前記硫酸過水で洗浄する工程、前記王水で洗浄する工程および前記フッ酸で洗浄する工程の各々において、処理時間を１５分以上とする、請求項１１に記載の炭化珪素基板の製造方法。 The method for producing a silicon carbide substrate according to claim 11, wherein a treatment time is 15 minutes or longer in each of the step of washing with sulfuric acid / hydrogen peroxide, the step of washing with aqua regia and the step of washing with hydrofluoric acid.
  13. 　前記王水で洗浄する工程において、王水と超純水とが混合された混合液における王水の体積濃度は５０％以上１００％以下である、請求項５から請求項１２のいずれか１項に記載の炭化珪素基板の製造方法。 The volume concentration of aqua regia in a mixed liquid in which aqua regia and ultrapure water are mixed is 50% or more and 100% or less in the step of washing with aqua regia. The manufacturing method of the silicon carbide substrate as described in any one of Claims 1-3.
  14. 　前記硫酸過水で洗浄する工程において、硫酸過水が含む硫酸の体積は硫酸過水が含む超純水の体積の１倍以上５倍以下であり、硫酸過水が含む過酸化水素水の体積は硫酸過水が含む超純水の体積の１倍以上３倍以下である、請求項７、請求項８、請求項１１および請求項１２のいずれか１項に記載の炭化珪素基板の製造方法。 In the step of washing with sulfuric acid / hydrogen peroxide, the volume of sulfuric acid contained in the sulfuric acid / hydrogen peroxide is 1 to 5 times the volume of ultrapure water contained in the sulfuric acid / hydrogen peroxide, and the volume of hydrogen peroxide contained in the sulfuric acid / hydrogen peroxide. The method for manufacturing a silicon carbide substrate according to any one of claims 7, 8, 11, and 12, wherein the volume of the ultrapure water contained in the sulfuric acid hydrogen peroxide is not less than 1 and not more than 3 times. .
  15. 　前記アンモニア過水で洗浄する工程において、アンモニア過水が含むアンモニア水溶液の体積はアンモニア過水が含む超純水の体積の１／１０倍以上１倍以下であり、アンモニア過水が含む過酸化水素水の体積はアンモニア過水が含む超純水の体積の１／１０倍以上１倍以下である、請求項７から請求項１０のいずれか１項に記載の炭化珪素基板の製造方法。 In the step of washing with ammonia overwater, the volume of the aqueous ammonia solution contained in the ammonia overwater is 1/10 to 1 time the volume of ultrapure water contained in the ammonia overwater. 11. The method for manufacturing a silicon carbide substrate according to claim 7, wherein the volume of water is 1/10 or more and 1 or less than the volume of ultrapure water contained in the ammonia perwater.
  16. 　前記洗浄する工程では、前記炭化珪素基板の温度を４０℃以下とする、請求項５から請求項１５のいずれか１項に記載の炭化珪素基板の製造方法。 The method for manufacturing a silicon carbide substrate according to any one of claims 5 to 15, wherein, in the cleaning step, a temperature of the silicon carbide substrate is set to 40 ° C or lower.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2016125404A1 (en) * 2015-02-02 2017-04-27 富士電機株式会社 Silicon carbide semiconductor device manufacturing method and silicon carbide semiconductor device
CN109571154A (en) * 2018-12-28 2019-04-05 天津洙诺科技有限公司 A kind of polishing method of 4H silicon carbide wafer
JPWO2019065994A1 (en) * 2017-09-29 2020-11-05 株式会社フジミインコーポレーテッド Polishing composition
WO2020235205A1 (en) * 2019-05-17 2020-11-26 住友電気工業株式会社 Silicon carbide substrate

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109321980B (en) * 2018-10-16 2019-11-19 山东天岳先进材料科技有限公司 A kind of high-flatness, low damage major diameter single crystal silicon carbide substrates
EP3666937B1 (en) * 2018-10-16 2023-07-05 Sicc Co., Ltd. High-flatness, low-damage and large-diameter monocrystalline silicon carbide substrate, and manufacturing method therefor
JPWO2020235225A1 (en) * 2019-05-17 2020-11-26
US11913135B2 (en) 2019-12-02 2024-02-27 Sumitomo Electric Industries, Ltd. Silicon carbide substrate and method of manufacturing silicon carbide substrate
KR102340307B1 (en) * 2020-04-09 2021-12-15 포항공과대학교 산학협력단 Forming ohmic contact on 4h-sic substrate semiconductor and manufacturing method thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11157989A (en) * 1997-11-25 1999-06-15 Toyo Tanso Kk Susceptor for gas phase growth and its production
JP2004014536A (en) * 2002-06-03 2004-01-15 Nec Electronics Corp Method of removing contaminant on semiconductor substrate
JP2008280207A (en) * 2007-05-10 2008-11-20 Matsushita Electric Ind Co Ltd METHOD FOR PRODUCING SiC SINGLE CRYSTAL SUBSTRATE
JP2009194216A (en) * 2008-02-15 2009-08-27 Hitachi Ltd Method of manufacturing semiconductor device
JP2011230959A (en) * 2010-04-27 2011-11-17 Kazuto Yamauchi METHOD FOR GRAPHENE FILM DEPOSITION ON SiC SUBSTRATE AND SiC SUBSTRATE WITH GRAPHENE
WO2013011751A1 (en) * 2011-07-20 2013-01-24 住友電気工業株式会社 Silicon carbide substrate, semiconductor device, method for producing silicon carbide substrate, and method for manufacturing semiconductor device

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100612853B1 (en) * 2004-07-21 2006-08-14 삼성전자주식회사 Si based material layer having wire type silicide and method of forming the same
US7514323B2 (en) * 2005-11-28 2009-04-07 International Business Machines Corporation Vertical SOI trench SONOS cell
DE102006011312B4 (en) 2006-03-11 2010-04-15 Fachhochschule Hildesheim/Holzminden/Göttingen - Körperschaft des öffentlichen Rechts - Apparatus for plasma treatment under atmospheric pressure
US8734661B2 (en) * 2007-10-15 2014-05-27 Ebara Corporation Flattening method and flattening apparatus
JP4887266B2 (en) * 2007-10-15 2012-02-29 株式会社荏原製作所 Flattening method
JP5267177B2 (en) * 2009-02-04 2013-08-21 日立金属株式会社 Method for manufacturing silicon carbide single crystal substrate
JP2011003769A (en) * 2009-06-19 2011-01-06 Panasonic Corp METHOD OF MANUFACTURING SiC SINGLE-CRYSTAL SUBSTRATE
JP5033168B2 (en) 2009-09-29 2012-09-26 忠弘 大見 Silicon carbide product, method for manufacturing the same, and method for cleaning silicon carbide product
CN104979184B (en) * 2011-10-07 2018-02-02 旭硝子株式会社 Monocrystalline silicon carbide substrate and lapping liquid
WO2013073216A1 (en) * 2011-11-14 2013-05-23 住友電気工業株式会社 Silicon carbide substrate, semiconductor device and methods for producing same
WO2013084934A1 (en) 2011-12-06 2013-06-13 国立大学法人大阪大学 Method for manufacturing solid oxide and device therefor
JP5803786B2 (en) * 2012-04-02 2015-11-04 住友電気工業株式会社 Silicon carbide substrate, semiconductor device and manufacturing method thereof
US9507254B2 (en) 2012-09-28 2016-11-29 Hoya Corporation Method of manufacturing substrate with a multilayer reflective film, method of manufacturing a reflective mask blank, substrate with a multilayer reflective film, reflective mask blank, reflective mask and method of manufacturing a semiconductor device
JP2014210690A (en) * 2013-04-22 2014-11-13 住友電気工業株式会社 Method for manufacturing silicon carbide substrate

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11157989A (en) * 1997-11-25 1999-06-15 Toyo Tanso Kk Susceptor for gas phase growth and its production
JP2004014536A (en) * 2002-06-03 2004-01-15 Nec Electronics Corp Method of removing contaminant on semiconductor substrate
JP2008280207A (en) * 2007-05-10 2008-11-20 Matsushita Electric Ind Co Ltd METHOD FOR PRODUCING SiC SINGLE CRYSTAL SUBSTRATE
JP2009194216A (en) * 2008-02-15 2009-08-27 Hitachi Ltd Method of manufacturing semiconductor device
JP2011230959A (en) * 2010-04-27 2011-11-17 Kazuto Yamauchi METHOD FOR GRAPHENE FILM DEPOSITION ON SiC SUBSTRATE AND SiC SUBSTRATE WITH GRAPHENE
WO2013011751A1 (en) * 2011-07-20 2013-01-24 住友電気工業株式会社 Silicon carbide substrate, semiconductor device, method for producing silicon carbide substrate, and method for manufacturing semiconductor device

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2016125404A1 (en) * 2015-02-02 2017-04-27 富士電機株式会社 Silicon carbide semiconductor device manufacturing method and silicon carbide semiconductor device
JPWO2019065994A1 (en) * 2017-09-29 2020-11-05 株式会社フジミインコーポレーテッド Polishing composition
US11773292B2 (en) 2017-09-29 2023-10-03 Fujimi Incorporated Polishing composition
CN109571154A (en) * 2018-12-28 2019-04-05 天津洙诺科技有限公司 A kind of polishing method of 4H silicon carbide wafer
WO2020235205A1 (en) * 2019-05-17 2020-11-26 住友電気工業株式会社 Silicon carbide substrate

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